CN103809356B

CN103809356B - screen

Info

Publication number: CN103809356B
Application number: CN201310463131.9A
Authority: CN
Inventors: 吴震
Original assignee: Individual
Current assignee: Yang yi
Priority date: 2013-08-02
Filing date: 2013-10-08
Publication date: 2019-12-10
Anticipated expiration: 2033-10-08
Also published as: CN103809356A

Abstract

The input light comprises first input light and second input light emitted from a first projection light source and a second projection light source which are different in position, and images carried by the first input light and the second input light are different. The screen comprises a microstructure layer, wherein the microstructure layer comprises at least one microstructure, and the microstructure comprises a first micro surface and a second micro surface; the first micro surface is used for receiving and projecting first input light as first output light, and the second micro surface is used for receiving and projecting second input light as second output light; the first output light and the second output light have different emission directions. The screen and the projection display system provided by the invention form different images in different directions, so that people at different positions can see different images, or two eyes of the same person can see different images, thereby forming a brand-new display effect.

Description

Screen

Technical Field

The invention relates to the technical field of display, in particular to a projection screen.

Background

Projection displays are currently being used in an increasing number of applications. The principle of projection display is that image light is projected onto a screen by a projector, the image light is scattered on the screen, and a part of the scattered image light is received by human eyes, and the image light appears to the human eyes as if it is emitted from the screen, so that an image is formed on the screen.

Projection displays are divided into front and rear projections. Front projection, i.e., the projector is on the same side of the screen as the viewer, and rear projection, i.e., the projector is on opposite sides of the screen as the viewer. For front projection, the screen functions to scatter and reflect image light, and for rear projection, the screen functions to scatter and transmit image light.

Disclosure of Invention

The invention provides a screen for receiving input light projected thereon. The input light comprises first input light and second input light emitted from a first projection light source and a second projection light source which are different in position, and images carried by the first input light and the second input light are different. The screen comprises a microstructure layer, wherein the microstructure layer comprises at least one microstructure, and the microstructure comprises a first micro surface and a second micro surface; the first micro surface is used for receiving and projecting first input light as first output light, and the second micro surface is used for receiving and projecting second input light as second output light; the emergent directions of the first output light and the second output light are different, so that when at least one point A on the screen is watched, a first visual angle range and a second visual angle range which are not overlapped with each other inevitably exist in the whole horizontal visual angle range, the first output light can be seen and the second output light cannot be seen in the first visual angle range, and the second output light can be seen and the first output light cannot be seen in the second visual angle range.

The invention also provides a screen for receiving input light projected thereon. The input light comprises first input light and second input light emitted from a first projection light source and a second projection light source which are different in position, and images carried by the first input light and the second input light are different; the screen comprises a Fresnel lens, the first input light transmits through the screen to form first output light, and the second input light transmits through the screen to form second output light; the emergent directions of the first output light and the second output light are different, so that when at least one point A on the screen is watched, a first visual angle range and a second visual angle range which are not overlapped with each other inevitably exist in the whole horizontal visual angle range, the first output light can be seen and the second output light cannot be seen in the first visual angle range, and the second output light can be seen and the first output light cannot be seen in the second visual angle range.

The screen provided by the invention forms different images in different directions, so that people at different positions can see different images, or two eyes of the same person can see different images, thereby forming a brand-new display effect.

Drawings

FIGS. 1 and 2 are two examples of the principles of operation of the projection display system of the present invention;

FIGS. 3a and 3b are top and side views, respectively, of one embodiment of a projection display system of the present invention;

FIG. 3c is a schematic diagram of an example of the microstructure on the screen in the embodiment of FIG. 3 a;

FIG. 3d is a schematic diagram showing the reflectivity of the first and second filters of FIG. 3c as a function of wavelength;

FIGS. 3e and 3f are schematic views of two further exemplary structures of the microstructure on the screen in the embodiment of FIG. 3 a;

FIG. 3g is a graph showing the reflectance of a light splitting layer of the microstructure of FIG. 3f as a function of wavelength;

FIGS. 3h and 3i are a variation of the microstructure shown in FIG. 3 f;

FIG. 4a is a top view of another embodiment of a projection display system of the present invention;

FIG. 4b is an example of the microstructure on the screen in the embodiment of FIG. 4 a;

FIG. 5a is a top view of another embodiment of a projection display system of the present invention;

FIGS. 5b and 5c are front and bottom views, respectively, of one example of a screen in the embodiment of FIG. 5 a;

FIGS. 5d and 5e are schematic views of microstructures at two locations on the screen in the embodiment of FIG. 5 a;

FIG. 5f is another exemplary front view of the screen of the embodiment shown in FIG. 5 a;

FIG. 5g is a three-dimensional schematic view of the microstructure of the screen shown in FIG. 5 f;

FIG. 6a is a top view of another embodiment of a projection display system of the present invention;

FIG. 6b is a front view of one example of the screen of the embodiment shown in FIG. 6 a;

FIGS. 6c and 6d are two examples of side views of the screen of the embodiment shown in FIG. 6 a;

FIG. 7 is a top view of another embodiment of a projection display system of the present invention;

FIGS. 8a to 8c show three further examples of the principle of operation of the projection display system of the present invention;

FIG. 9 is a schematic illustration of the effect of a scattering layer on ray angle;

fig. 10a to 10c are schematic views of a modification of the microstructure of fig. 5e to the working principle of fig. 8a to 8 c;

FIG. 11 is another example of the principle of operation of the projection display system of the present invention;

fig. 12a and 12b are schematic views of a modification of the microstructure of fig. 5e to the working principle of fig. 11.

Detailed Description

Fig. 1 and 2 are examples of two modes of operation of the present invention for a projection display system. In fig. 1, the screen 101 is configured to receive input light (input light is not shown), and project at least part of the input light into two first output light 111 and two second output light 112 respectively carrying different images, and exit directions of the first output light 111 and the second output light 112 are different. In the present invention, the light beam "carrying" an image means that the light beam is modulated according to an image signal to carry image information, and "projecting" is understood to be emitting in a specific direction or a specific range of directions. In the figure, the eyes 141 and 142 represent the positions of two persons, respectively, and it can be seen that three rays representing the first output light 111 are incident on the eye 141, and three rays representing the second output light 112 are incident on the eye 142. Thus eye 141 is able to see the image carried by first output light 111 and no image carried by second output light 112 on screen 101, while eye 142 is able to see the image carried by second output light 112 and no image carried by first output light 111 on screen 101. The advantage of this is that only the same screen is used, occupying a single screen space, to provide different image displays for people in different orientations. The advertisement can be obviously applied to various fields, such as show window advertisements, and the same pedestrian can see different advertisement contents in different positions, so that the advertising purpose is achieved, and meanwhile, the cost is saved.

the screen 201 in fig. 2 functions close to that of fig. 1, except that the exit directions of the first output light 211 and the second output light 212 are closer, and the eyes 241 and 242 represent the left and right eyes of the same observer, respectively. Similarly, the eye 241 can see the image carried by the first output light 211 and cannot see the image carried by the second output light 212 on the screen 201, while the eye 242 can see the image carried by the second output light 212 and cannot see the image carried by the first output light 211 on the screen 201, i.e. the two eyes of the viewer see different image contents. Thus, as long as the image contents of the first output light 211 and the second output light 212 are controlled to correspond to the images of the left eye and the right eye in the 3D image, respectively, the observer can see the 3D image effect.

The operation of the projection display system and screen of the present invention is described above using only two examples. The following describes a specific implementation method of the projection display system and the screen thereof with reference to the accompanying drawings.

In the following description, if not specifically stated:

1. The input light is represented by dotted lines, the first output light is represented by solid lines, and the second output light is represented by dashed lines;

2. for convenience of explanation, the up-down angle direction is equal to the vertical angle direction of the screen, and the left-right angle direction is equal to the horizontal angle direction of the screen;

3. The first output light is directed to the left and the second output light is directed to the right, but this is by way of example only and not by way of limitation.

fig. 3a is a top view of a projection display system according to a first embodiment of the present invention. The projection light source 351 is located in the middle of the screen 301 in the left-right direction, and is located on the same side of the screen 301 as the observer. The screen 301 thus functions to reflect light emitted from the projection light source 351 so that it can be seen by an observer. Input light (two of the light rays 321a and 321 b) indicated by dotted lines is emitted from the projection light source 351 and projected on the screen 301, and the irradiation range of the input light covers the entire screen range. The light rays 321a and 321b are used as examples to illustrate the reflection effect of the screen 301. After the light ray 321a is incident on the 301a area on the screen, the screen is divided into two parts, the two parts of light are reflected by the screen to different directions to form output light rays 311a and 312a, the light ray 311a is projected to the left, and the light ray 312a is projected to the right. After the light ray 321b is incident on the 301b area on the screen, the screen is divided into two parts, the two parts of light are reflected by the screen to different directions to form output light rays 311b and 312b, the light ray 311b is projected to the left, and the light ray 312b is projected to the right.

Fig. 3b is a side view of the projection display system shown in fig. 3 a. The projection light source 351 is located at the lower portion in the up-down direction of the screen 301, and the light ray 321a is reflected by the screen 301 as the output light rays 311a and 312a, and the light ray 321b is reflected by the screen 301 as the output light rays 311b and 312 b.

As can be seen from fig. 3a and 3b, the screen 301 functions to control the incoming light rays 321a and 321b to be reflected to form output light in a specific direction in the left-right angular direction and the up-down angular direction, respectively. In the screen and the projection display system described in the present invention, the focus is on the control method of the input light and the output light in the left-right angular direction of the screen, and the prior art method can be used for the control of the input light and the output light in the up-down angular direction. For example, the most common method is to scatter light sufficiently in the up-down angular direction so that the input light incident from below the screen does not directly go out upward by being specularly reflected in the up-down angular direction, but is scattered to cover a considerable range in the up-down angular direction to ensure that part of the reflected light can be incident on the eyes of the observer. For example, another common method is to use microstructures on the screen to directionally reflect the input light incident from below the screen (see fig. 6c and 6 d) to the viewer's eye, which has the advantage of greater intensity of light incident on the viewer's eye, and the disadvantage of small angular coverage of the reflected light, i.e., small range of viewing angles from the viewer's perspective. It is understood that these two control methods for the light rays in the up and down angular directions can also be used in combination. No matter which control method for the light rays in the up-down angle direction is used, the effect of the invention is not influenced. The method for controlling the light rays in the left-right angle direction can be used in combination with any method for controlling the light rays in the up-down angle direction, and the invention is not limited thereto.

fig. 3c and 3e are schematic structural diagrams of a middle area 301b and an area 301a to the right on the screen in fig. 3a, respectively, and the operation method of the screen 301 in this embodiment will be described below with reference to fig. 3c and 3e, respectively.

A method of how to achieve reflection of input light ray 321b in different directions in left and right angular directions to form output light rays 311b and 312b on the central region 301b is first described in connection with fig. 3 c. In the area 301b on the screen, at least one prism unit 302b is included, which forms a prism array (only one prism unit 302b is labeled for illustration in fig. 3 c). The prism unit 302b includes two surfaces, a first surface and a second surface, which are different in normal direction, facing the incident direction of the input light. The first surface of the prism unit is coated with a first filter 304b, so that the input light 321b incident on the first surface is split into two beams, one beam is the reflected light 311b and the other beam is the transmitted light 331b, wherein the transmitted light 331b is absorbed by the absorption layer 303b disposed behind the prism array. The second surface of the prism unit is coated with a second filter 305b such that the input light 321b incident on the second surface is split into two beams, one beam is the reflected light 312b and the other beam is the transmitted light 332b, wherein the transmitted light 332b is absorbed by the absorption layer 303b disposed behind the prism array.

In this embodiment, the first filter and the second filter divide the input light 321b into two parts according to the wavelength, and the variation curve of the reflectivity of the first filter and the second filter with the wavelength is shown in fig. 3 d. In FIG. 3d, the broken line shown as a solid line is the reflectivity curve of the first filter 304B, which includes three high reflectivity regions 304B-B (corresponding to the blue spectral region), 304B-G (corresponding to the green spectral region), and 304B-R (corresponding to the red spectral region); the broken line shows the reflectivity curve of the second filter 305B, which includes three high reflectivity regions 305B-B (corresponding to the blue spectral region), 305B-G (corresponding to the green spectral region), 305B-R (corresponding to the red spectral region); the three high-reflectivity regions of the first filter film and the three high-reflectivity regions of the second filter film are mutually crossed in wavelength. At this time, the projection light source 351 may be arranged such that the input light 321B simultaneously carries two images, a first image having three spectral bands corresponding to 304B-B, 304B-G, and 304B-R as the three primary colors, and a second image having three spectral bands corresponding to 305B-B, 305B-G, and 305B-R as the three primary colors. Thus, the first image is reflected by the first filter 304b on the first surface of the prism 302b as the first output light 311b, and the second image is reflected by the second filter 305b on the second surface of the prism 302b as the second output light 312 b.

Two images carried by input light of the projection light source can be emitted simultaneously or in a time-sharing manner. This is prior art and is only exemplified here for its implementation. When two images are simultaneously emitted, two image lights are respectively generated according to two input image signals, and then the two image lights are combined into one beam by using optical filters with different spectrums. Another situation that another image is emitted simultaneously is that two image lights are respectively generated according to two input image signals, and the two image lights are respectively projected to a screen through adjacent lenses, so that the two image lights are also approximately one beam due to the closer proximity. In the case of two images emitted in a time-sharing manner, a color wheel containing two sets of three primary colors in fig. 3d may be used in the projection light source to generate two sets of primary colors in a time-sharing manner, and the light valve respectively and synchronously modulates the two sets of primary colors according to the two input image signals to generate two image lights emitted in a time-sharing manner.

Fig. 3e is a schematic structural diagram of the area 301a to the right on the screen in fig. 3 a. Unlike the area 301b shown in fig. 3c, the prism array in fig. 3e includes two prism units 302a, each of which has a surface irradiated by the input light 321a, and the two surfaces are the surface 304a and the surface 305a, respectively, and the normal directions of the two irradiated surfaces are different. Thus, by coating the first filter 304a and the second filter 305a on the two surfaces, respectively, the input light can be divided into two output lights 311a and 312a with different wavelength ranges and projected in different directions. It can be understood that the main difference between the screen structure in fig. 3e and the screen structure in fig. 3c is that, in fig. 3c, two surfaces of the same prism are utilized to split the input light into two beams, i.e., a first input light and a second input light, and reflect and project the two beams into a first output light 311b and a second output light 312b, respectively; whereas in figure 3e one surface of each of the two prisms is used for the same purpose.

FIG. 3e is a schematic diagram of the structure of the area 301a to the right on the screen in FIG. 3a, wherein the input light 321a is incident from the left side, and therefore the first filter 304a and the second filter 305a are respectively coated on the left surfaces of the two prism units to face the incident light; it can be understood that for the left area on the screen, since the input light will be incident from the right side, the first filter and the second filter are coated on the surfaces of the right sides of the two corresponding prism units to face the incident light. The description is not repeated for the left region on the screen. In the following embodiments, the middle and right regions of the screen are taken as examples for illustration, and the left side of the screen can be correspondingly derived according to the structure of the right side.

It is easily understood that, in the screen of the present embodiment, the structure of the middle region 301b is different from that of the edge region 301a, mainly because the projection light source 351 is located in the middle of the screen in the left-right direction, resulting in a large difference in the incident angles of the input light incident on the region 301b and the region 301 a. In practice, there is no such limitation. For example, when the projection light source is located on the left side of the screen, the light rays at each position are incident from the left side for the whole screen range, and then the structure on each area on the screen can be designed easily by those skilled in the art according to the description of fig. 3e, and in this case, the structure shown in fig. 3c may not be adopted.

It should be noted that, in practical applications, the positions of the first filter film and the second filter film are not necessarily on the surface of the prism facing the incident direction of the input light, and may also be on the surface of the prism facing the absorption layer. Furthermore, the first and second filters may themselves be absorbing filters, so that the function of the absorbing layer is integrated in the filters, in which case the absorbing layer may be omitted.

Since the input light is projected from the projection light source onto the screen, the incident cone angle of the input light incident on any position a on the screen is very small (the solid angle of the cone angle is equal to the ratio of the aperture of the projection lens of the projection light source to the distance from the projection lens to the position a), and therefore, in the present embodiment, the exit direction of the output light can be accurately controlled by the prism unit designed on the screen. This is the essential reason why the present invention has excellent effects.

In addition to fig. 3c, fig. 3f is another schematic diagram of the structure of the middle 301b area on the screen in fig. 3 a. In this configuration, input light 321b is first incident on a prism array (only one prism 307b is shown for illustration). In this embodiment, a surface of the prism 307b facing away from the incident direction of the input light is attached with a light splitting layer 308b (in practical applications, the light splitting layer may be directly plated on the surface of the prism), which can split the incident light into two beams of transmission and reflection according to the difference of wavelengths. The light splitting layers on different prisms in the prism array also form a light splitting layer array, and in this embodiment, the light splitting layer arrays are all in the same plane and have the same properties, so the light splitting layer array should form an integral light splitting layer. The input light 321b is refracted by the prism 307b and then deflected and enters the light splitting layer 308b, a beam of light reflected by the light splitting layer 308b is refracted by the prism 307b again and then exits to form a first output light 311b, and a beam of light transmitted by the light splitting layer 308b enters the reflection layer 309b located at the rear end of the light path of the light splitting layer 308b, is reflected on the surface of the reflection layer, then transmits the light splitting layer 308b again, and exits to form a second output light 312b after being refracted by the prism 307 b. Since the light paths of the transmitted light and the reflected light are different in the spectroscopic layer 308b, the first output light 311b and the second output light 312b formed by them respectively have different emission directions. Specifically, the exit direction of the first output light 311b can be controlled by controlling the shape of the prism 307b, and further the direction of the second output light 312b can be controlled by controlling the reflective layer 304b, so that the purpose of controlling the directions of the two output lights is achieved.

In the present embodiment, the reflective layer 309b is an array of reflective units, each of which is zigzag-shaped in the horizontal direction, and the vertical angle of the zigzag is 90 degrees in the horizontal direction, so that it can reflect the incident light in the original direction according to the geometric knowledge. In practice the apex angle of the saw tooth may not be 90 degrees and controlling this angle may achieve the purpose of controlling the direction of the reflected light. In addition, there are many methods for implementing a reflective layer, such as directly using a metal film or a dielectric film plated on a substrate having a certain structure, controlling the direction of reflected light by controlling the shape of the structure, and using a glass bead array to achieve the purpose of reflecting incident light in the original direction.

FIG. 3g shows the reflectance of the light splitting layer 308b of FIG. 3f as a function of wavelength. Three high-reflectance regions 308b-rB (corresponding to the blue spectral region), 308b-rG (corresponding to the green spectral region), and 308b-rR (corresponding to the red spectral region) are included in the figure, and three high-transmittance regions 308b-tB (corresponding to the blue spectral region), 308b-tG (corresponding to the green spectral region), and 308b-tR (corresponding to the red spectral region) are included in the cleft of these three high-reflectance regions. It can be understood that, in the two light beams split by the splitting layer 308b, the reflected light beam has three primary colors corresponding to the three high-reflectivity regions, and the transmitted light beam has three primary colors corresponding to the three high-transmissivity regions. Thus, the projection light source 351 is arranged such that the input light 321b simultaneously carries two images, one image having three spectral bands corresponding to 308b-rB, 308b-rG, and 308b-rR as the three primary colors, and the other image having three spectral bands corresponding to 308b-tB, 308b-tG, and 308b-tR as the three primary colors. Thus, the two images are divided into two beams, i.e., a first input light and a second input light, inside the screen, and are reflected to different directions to form a first output light 311b (311 a) and a second output light 312b (311 a), respectively. Two images carried by input light of the projection light source can be emitted simultaneously or in a time-sharing manner, and are not limited.

fig. 3h and 3i are a variation of the structure shown in fig. 3f, the structure of fig. 3h being applied to the middle area 301b of the screen 301 and the structure of fig. 3i being applied to the right area 301a of the screen 301.

in the structure shown in fig. 3h, the light splitting layer 308b is plated on the surface of the prism 307b facing the input light direction, the input light 321b is incident on the light splitting layer 308b and then split into two beams, the reflected portion forms the output light 311b, the transmitted portion passes through the prism 307b and then is reflected by the reflecting layer 309b, and the transmitted portion passes through the prism 307b and then the light splitting layer 308b again to form the output light 312 b. This construction differs from that shown in figure 3f only in the order of the components and the shape of the reflecting layer, which the skilled person can design himself in light of the description, and thus falls within the scope of the present invention. In this embodiment, the light splitting layers on each prism of the prism array form an array, and these light splitting layers are not necessarily on the same plane, and cannot form an integral light splitting layer.

In the structure shown in fig. 3i, the reflective layer 309a is an array of reflective elements, wherein only one reflective element 309a is shown, and the reflective element 309a is saw-toothed. The input light 321a enters the light splitting layer 308a on the surface of the prism 307a from the left direction, and the shape of the prism 307a is adjusted accordingly so that the exit direction of the reflected light portion 311a is controlled, and meanwhile, the transmitted portion is reflected once by the reflection unit array 309a and exits after being refracted by the prism 307a to form the output light 312 a. As can be understood by comparing the differences of fig. 3i and fig. 3h, the skilled person can design the output direction of the output light differently for different positions of the screen according to the above description.

In the above embodiments, the first filter, the second filter, and the light splitting layer filter or split light according to the wavelength. In practical applications, the light may be filtered or split according to the different polarization states. For example, in the configurations shown in fig. 3c and 3e, the first filter can reflect polarized light in the a direction and transmit or absorb polarized light in the B direction, and the second filter can reflect polarized light in the B direction and transmit or absorb polarized light in the a direction, where the a direction and the B direction are perpendicular to each other. For another example, in the structures shown in fig. 3f, 3h and 3i, the light splitting layer may reflect the a-direction polarized light while transmitting the B-direction polarized light, and the a-direction and the B-direction are perpendicular to each other. Thus, as long as the projection light source is arranged so that the input light simultaneously carries two images, one image is carried by polarized light in the direction a, and the other image is carried by polarized light in the direction B, the two images are divided into two beams inside the screen and respectively reflected to different directions to form first output light and second output light. Two images carried by input light of the projection light source can be emitted simultaneously or in a time-sharing manner, and are not limited.

in the structures shown in fig. 3f to 3i, only one prism unit, one beam splitting layer unit and one reflection unit are shown, and in practical applications, a prism array composed of a plurality of prisms and a reflection array composed of a plurality of reflection units are possible. The prism units and the reflection units do not necessarily correspond to each other, and the transmission light transmitted through one prism unit may be incident on the other prism unit after being reflected by the reflection unit. In addition, the reflective layer may also be integrated with the prism. Therefore, the optical path designs of fig. 3f to 3i are only for illustration and not for limitation.

It is emphasized that the structures shown in fig. 3f to 3i are more efficient than the structures shown in fig. 3c to 3 e. This is because part of the light is absorbed in the former, while the input light in the latter is split into two beams, both of which are used.

As can be seen from the embodiments shown in fig. 3a to 3i, the screen 301 divides the input light into two beams according to the difference of specific optical properties, a first input light and a second input light, the first input light is projected to form a first output light, the second input light is projected to form a second output light, and the two beams of output light carry different images and have different exit angles. Including but not limited to wavelength and polarization state. By utilizing the design of the screen, the precise control of the angles of the two beams of output light can be realized.

In the embodiments shown in fig. 3a to 3i, the screens are all reflective, i.e. the viewer is on the same side of the screen as the projection light source. In practice, the screen may also be of a transmissive type, i.e. the viewer and the projection light source are on opposite sides of the screen. As shown in fig. 4a, light emitted from the projection light source 451 (for example, the light ray 421 b) is transmitted through the screen 401, and then two output lights (for example, the light rays 411b and 412 b) are formed and projected in different directions.

fig. 4b is a schematic structural diagram of a region 401b on the screen in fig. 4 a. The input light 421b is incident on the prism array (only one prism 402b is shown schematically) and is incident on two surfaces of each prism, which have different normal directions and are respectively coated with different filters, a first filter 404b and a second filter 405 b. After the input light 421b is filtered by the first filter film 404b, part of the light is transmitted through the prism surface and refracted by the prism to form the output light 411b, and the reflected light 431b is reflected back to the direction of the projection light source. After the input light 421b is filtered by the second filter film 405b, part of the light transmits through the prism surface and is refracted by the prism to form the output light 412b, and the reflected light 432b is reflected back to the direction of the projection light source. At this time, as long as the input light projected by the projection light source carries two different images, the spectrums of the primary light used by the two images correspond to the transmission spectrums of the first filter film and the second filter film, respectively, and the output light projected in different directions of the different images can be realized.

As can be understood by comparing fig. 3c and fig. 4b, the two principles are similar, and the difference is that the structure of fig. 3c is a reflection type structure and the structure of fig. 4b is a transmission type structure, so that the relationship between the transmittance and the wavelength of the first filter and the second filter can be expressed by changing the ordinate of fig. 3d to "transmittance". In practical applications, the modifications of the structure of fig. 3c shown in fig. 3e, 3f, 3h, and 3i can be applied to the transmission type design, and are not described herein again.

In the above embodiment, only one projection light source is used to generate input light, the input light carries two different images according to different optical properties such as wavelength or polarization state, the two images are separated on the screen according to different optical properties such as wavelength or polarization state to form a first input light and a second input light, and the first input light and the second input light are projected as a first output light and a second output light with different emission directions through different optical paths inside the screen. In practice, two projection light sources may be used to generate the first input light and the second input light from different positions, respectively, and the first input light and the second input light carry different images (as shown in the following embodiments). The first input light is projected by the screen to form first output light, and the second input light is projected by the screen to form second output light. If the two images are temporally related, for example, the two images respectively correspond to a left-eye image and a right-eye image of a person for realizing a 3D effect, it is necessary to control the first input light and the second input light output by the two projection light sources to be synchronized. If the two images are not correlated, no synchronization control is required.

A top view of a projection display system according to another embodiment of the present invention is shown in fig. 5 a. The projection display system includes two projection light sources, a first projection light source 551 and a second projection light source 552 are respectively located on both sides of the screen 501 in the left-right direction, a first input light (only two light rays 521a and 521b are drawn to illustrate in the figure) emitted by the first projection light source 551 is projected onto the screen 501 from the left side, and a second input light (only two light rays 522a and 522b are drawn to illustrate in the figure) emitted by the second projection light source 552 is projected onto the screen 501 from the right side. Both rays 521a and 522a are incident on the right area 501a on the screen, and both rays 521b and 522b are incident on the middle area 501b on the screen. The right region 501a reflects the first input light 521a to form a first output light 511a, and reflects the second input light 522a to form a second output light 512a, where the first output light 511a and the second output light 512a have different directions. Similarly, the central region 501b reflects the first input light 521b to form a first output light 511b, and reflects the second input light 522b to form a second output light 512b, where the directions of the first output light 511b and the second output light 512b are different. The first output lights 511a and 511b are directed in the same direction and viewed by the observer, so that the observer in this direction can simultaneously see the first output lights coming from different positions on the screen to form a complete image; similarly, the viewer in the emitting direction of the second output lights 512a and 512b can also see the second output lights emitted from different positions on the screen to form a complete image.

In practical applications, in order to meet special requirements including 3D display, the projection display system may further include an image synchronization control device (not shown) for controlling the first projection light source 551 and the second projection light source 552 to synchronize images carried by the first input light and the second input light with each other.

Fig. 5b to 5e show an example of the structure of the screen 501, and the following description is made with reference to these figures. Fig. 5b is a front view of the system shown in fig. 5 a. The screen includes a microstructured layer, which in this embodiment is a prism array. Each prism in the prism array includes two surfaces, a first micro-facet and a second micro-facet, facing the input light. The first micro surface and the second micro surface are attached with reflecting layers, and specifically, the reflecting layers can be metal reflecting layers or medium reflecting layers plated on the surfaces of the first micro surface and the second micro surface. Fig. 5c is a bottom view of the screen 501. It should be noted that the prism arrays in fig. 5b and 5c do not represent true dimensions and proportions, and the size of the prisms in the prism arrays relative to the screen is much smaller in practical applications than that shown in the figures; here shown enlarged for convenience of illustration.

Fig. 5d shows the working principle of the area 501b on the screen. Fig. 5d is a top view of a prism, two surfaces of the prism facing the input light are a first micro surface 504b and a second micro surface 505b, and the surfaces of the first micro surface 504b and the second micro surface 505b are coated or plated with a reflective film. The first micro-surface 504b faces the first input light 521b, receives and projects the first input light 521b as a first output light 511b, and the second micro-surface 505b faces the second input light 522b, receives and projects the second input light 522b as a second output light 512 b. Thus, by controlling the shape of the prism, i.e., controlling the normal directions of the first micro-surface 504b and the second micro-surface 505b, the exit directions of the first output light 511b and the second output light 512b can be precisely controlled. It is also noteworthy that the first micro-facet 504b is not facing the second input light 522b while facing the first input light 521b, such that the second input light 522b does not impinge on the first micro-facet 504 b; similarly, the second micro-surface 505b faces the second input light 522b and does not face the first input light 521b, and the first input light 521b does not irradiate the second micro-surface 505b, so that the crosstalk between the first output light and the second output light can be minimized. In fact, even if a small portion of the first input light enters the second micro-surface, the normal direction of the second micro-surface is not proper, and the portion of the first input light is not projected to the exit direction of the second output light to form crosstalk.

Fig. 5e shows the operation of the area 501a to the right on the screen 501. In fig. 5e, a top view of a prism is shown, the two surfaces of the prism facing the input light are a first micro-facet 504a and a second micro-facet 505a coated with a reflective film. The first micro-surface 504a is configured to receive and project the first input light 521a as the first output light 511a, and the second micro-surface 505a is configured to receive and project the second input light 522a as the second output light 512 a. Slightly different from the prism in fig. 5d, the angle of the incident light is different because the position of the region 501a is different from the position of the region 501b, so that the shape of the prism, i.e. the normal directions of the first and second facets, need to be adjusted so as to control the exit directions of the first output light 511a and the second output light 512 a. Specifically, the area 501a is on the right side of the screen, so that the incident direction of the first input light is smaller (i.e. closer to the direction parallel to the screen) and the incident direction of the second input light is larger (i.e. closer to the direction perpendicular to the screen) compared to the area 501b, so that in order to achieve the first output light 511a having substantially the same exit direction as the first output light 511b reflected from the middle of the screen, the second output light 512a has substantially the same exit direction as the second output light 512b reflected from the middle of the screen, and the prism in fig. 5e is more deviated to the left than the prism center in fig. 5 d.

According to the above design concept, those skilled in the art can design the prism shape at different positions of the whole screen, and the details are not described herein.

In the systems shown in fig. 5b to 5e, the microstructure layer is an array of prisms arranged in parallel extending in a vertical direction. In practice, if the first projection light source and the second projection light source are respectively disposed above and below the screen, the micro-structure layer may also be a prism array extending in a horizontal direction and arranged in parallel. Therefore, the extending direction of the prism and the arrangement direction of the projection light source are not limited by the invention. In addition, although the prisms are protruded from the screen body in fig. 5b to 5e, the prisms may actually be recessed (recessed is also referred to as prisms), and two micro-surfaces formed by the recessed portions may also play a role of reflecting the first input light and the second input light respectively.

In the screen structures shown in fig. 5b to 5e, the disadvantage is that the light control of the screen in the up-down angular direction is not good, for example, in the upper area of the screen, the exit angle of the reflected light formed by reflecting the input light from the lower position than the area is higher, this can be solved by using a scattering layer, which can be placed in front of the screen (i.e., the input light is incident on the scattering layer first and then incident on the screen), or can be a part of the screen, for example, a scattering particle layer is formed on the surface of the microstructure, and then, for example, the surface of the microstructure is roughened, in this embodiment, the microstructure faces the input light, while in practical application, the microstructure may face back the input light (see fig. 6 d), i.e., the input light must be transmitted through the screen body before being incident on the surface of the microstructure, and the scattering particles may be doped into the screen body, and, for achieving directional control in the up-down angular direction and left-right angular direction at the same time, in order to achieve directional control in the up-down angular direction, the scattering layer is preferably, the scattering layer has been doped with a scattering angle smaller than in the up-down angular direction, for example, the scattering layer is also a cylindrical structure, and the structure is formed by using a method of the same method as described in the prior art, and the invention, and the method of controlling the structure, which is also can be applied to control of the up-down angular direction, and the structure, and the method of controlling the structure, and the method of the technology of the structure, such as described here, the technology, the structure, the technology of the.

another method for solving the problem of poor light control in the up-down angle direction of the screen structure shown in fig. 5b to 5e is to improve the screen structure, as shown in fig. 5 f. Fig. 5f is a front view of another screen structure in which the microstructure of the microstructured layer is different from that shown in fig. 5 b. In the screen of the embodiment shown in fig. 5f, the microstructure layer comprises several irregularly shaped microstructures, of which 4 are depicted (for convenience, not drawn to scale, the actual microstructures are much smaller), microstructures 5011, 5014, 5017 and 5018. First, the operation principle of each microstructure is described by taking the microstructure 5011 as an example.

Fig. 5g is a schematic perspective view of the microstructure 5011, wherein the surface of the microstructure 5011 includes two micro-surfaces, a first micro-surface 5012 and a second micro-surface 5013, which are shown in fig. 5f by the intersection lines of the two micro-surfaces and the screen body. In fig. 5g, the first micro-facet 5012 faces the first projection light source 551 substantially, and its intersection line with the screen body is on a circle with the light outlet of the first projection light source 551 as the center. Thus, the problem of poor control of the light in the vertical direction is effectively avoided, the first micro-facet 5012 can reflect the first input light 521 as the first output light 511, and the direction of the first output light 511 is controllable in the vertical angular direction and the horizontal angular direction. For the same reason, the second micro-facet 5013 is used to reflect the second input light 522 into the second output light 512, and the second micro-facet 5013 is substantially facing the second projection light source 552, and its curved surface shape is used to control the exit direction of the second output light 512. The second micro-surface 5013 is slightly different from the first micro-surface 5012 in that the intersection line of the second micro-surface 5013 and the screen body is a straight line segment rather than a curved line segment, and the straight line segment is tangent to a circle with the light outlet of the second projection light source as the center. The effect is similar to that of a curved section due to the shorter length of the straight section, but it is much easier to process. Further, the intersection line of the first micro surface and the screen body can be also approximate to a straight line segment, so that the whole micro structure 5011 is a pyramid structure, and the processing difficulty is low. In fact, the top of the microstructure 5011 may also be not a sharp top but a line or a flat top. The invention is not limited to these microstructural variations.

It can be seen that for the microstructure 5011, the first micro-facets 5012 face the first projection light source and not the second projection light source, while the second micro-facets 5013 face the second projection light source and not the first projection light source. The other two surfaces of the microstructure 5011 are preferably designed to face the first projection light source and the second projection light source as little as possible, that is, to be irradiated by the first input light and the second input light as little as possible. The two surfaces are therefore designed to extend in the direction of the radiation emerging from the light exit opening of the first projection light source or in the direction of the radiation emerging from the light exit opening of the second projection light source. As can be seen from fig. 5f, with the microstructure 5011, the facets thereof located below the first and second facets 5012 and 5013 extend in the direction of the radiation from the light exit of the first projection light source 551, and the facets of the microstructure 5011 located above the first and second facets 5012 and 5013 extend in the direction of the radiation from the light exit of the second projection light source 552. Even if the two micro-surfaces are irradiated by the input light, the normal direction is not proper, so that the crosstalk of the image is not caused, but stray light is formed, and the efficiency of the screen is reduced. Compared with the microstructures in fig. 5d and 5e, since the design of the microstructure in fig. 5g is not limited to extend along a specific direction, the microstructure in fig. 5g has a larger degree of freedom in design, and can more accurately control the direction (left-right angle direction and up-down angle direction) of the output light.

The arrangement of the microstructures is explained below with the microstructures 5014, 5017, and 5018. The microstructure 5014 includes first and second facets 5015 and 5016 facing the first and second projection light sources 551 and 552, respectively. The structural design method is the same as the microstructure 5011, and repeated description is omitted. The microstructures 5017 and 5018 are located side-by-side below the microstructure 5014. It can be seen that in order to satisfy the condition that the first and second facets are facing the first and second projection light sources 551 and 552, respectively, the microstructures 5014, 5017, and 5018 cannot be completely contiguous to each other, but there is a blank area, unlike the structure shown in fig. 5 b. It will be appreciated that this void area is small enough as long as the microstructure is small enough.

Unlike the embodiment shown in fig. 5a, in another embodiment shown in fig. 6a, the first and second projection light sources 651 and 652 are no longer located at opposite sides of the screen, but are simultaneously located at the lower side of the screen and are separated by a certain distance in the left-right direction (refer to fig. 6 b). In this way, the purpose of respectively projecting the first input light and the second input light to form the first output light and the second output light with different emergent directions can also be achieved through the screen 651. This is explained in detail below with reference to fig. 6 b.

In fig. 6b, a plurality of microstructures is included on a screen 601, of which only 4 microstructures 6011, 6014, 6015, and 6016 are shown. First, the microstructure 6011 is taken as an example to describe the working method. Similar to the embodiment shown in fig. 5g, the microstructure 6011 is a convex microstructure and comprises three facets, two of which face below the screen, a first facet 6012 is facing the first projection light source 651, and a second facet 6013 is facing the second projection light source 652. In fig. 6b, the first and second facets are each represented by the intersection of these two facets with the screen body. The first input light 621 is incident on the first micro-surface, and the direction of the reflected light, that is, the emitting direction of the first output light 611 can be controlled by controlling the normal direction of the first micro-surface 6012. Similarly, the second input light 622 is incident on the second micro-surface, and the direction of the reflected light, that is, the emitting direction of the second output light 612, can be controlled by controlling the normal direction of the second micro-surface 6013.

Since the first projection light source and the second projection light source are both located below the screen and not opposite to each other, there are positions on the screen where the first facets of the microstructures will face partially the second projection light source or the second facets of the microstructures will face partially the first projection light source. In the present invention, the surface X "faces" the object Y, meaning that at least one of the radiation emitted from Y falls on the surface X, and the surface X "does not face" the object Y, meaning that the radiation emitted from Y cannot fall on the surface X at all. For example, in the present embodiment, the first input light 623 emitted from the first projection light source is incident on the second micro-surface 6013 and is reflected as stray light 613. This causes a reduction in screen efficiency, but since the exit direction of the ray 613 is different from the direction of the second output light 612, no crosstalk between the two images is formed.

The arrangement between the microstructures in this embodiment is described below with respect to microstructures 6014, 6015, and 6016. Preferably, two groups of concentric circles can be drawn by respectively taking the light outlet of the first projection light source and the light outlet of the second projection light source as the centers of circles, the screen is divided into small blocks by the two groups of concentric circles, and each small block is filled with one microstructure, so that the condition that each microstructure is provided with two first micro surfaces and two second micro surfaces which respectively face the first projection light source and the second projection light source can be met. It can be seen that, in the present embodiment, the microstructures may be triangular pyramids or triangular truncated pyramids as shown in fig. 6b, but is not limited thereto, and since the structure of the upper half of each microstructure is not limited (the upper half of each microstructure in fig. 6b is blank), the outer shape of each microstructure may also fill the small blocks divided by two sets of concentric circles, as long as the angles of the first and second facets are not affected.

Fig. 6c and 6d show two examples of side views of the screen in this embodiment. In fig. 6c, the microstructured layer faces input light 621 and 622, which is directly reflected by the microstructured layer to form output light 611 and 612. By controlling the form of the microstructure in the microstructure layer, the emergent angles of the output light in the vertical direction and the horizontal direction can be controlled. Fig. 6d is another example, in which the microstructured layer faces away from the input light 621 and 622, which first transmits the body of the screen 601 and then enters the surface of the microstructured layer, where it is reflected to form the output light 611 and 612. It will be appreciated that in the embodiments of fig. 5a to 5g, the microstructured layer may also face away from the input light.

In the embodiment shown in fig. 5a to 6d, the screens are reflective, and a specific way of using a transmissive screen in combination with two projection light sources is described below with reference to fig. 7. As shown in fig. 7, the first and second projection light sources 751 and 752 are located at both sides of the screen 701 with the viewer. The screen 701 has a fresnel lens structure, the first projection light source 751 is located at the right position of the center of the screen, and the first input light 721 emitted by the first projection light source is transmitted through the screen 701 and converged to form first output light 711 which is directed to a viewer at the left side; the second projection light source 752 is located at a position to the left of the center of the screen, and the second input light 722 emitted by the second projection light source is transmitted through the screen 701 and converged to form second output light 712, and is directed to the observer at the right side. In this embodiment, the input light is converged and transmitted by using the structure of the fresnel lens of the screen 701, and the first output light and the second output light with different exit directions are formed by using the difference of the incident directions of the first input light and the second input light.

The above description of how to control the emission directions of the first output light and the second output light, and how to precisely control the direction of each ray of the output light, has been described with different embodiments of projection display systems and screen structures, from fig. 3a to 7. Meanwhile, fig. 1 and fig. 2 respectively illustrate the light distribution of the two first output light and the second output light that can be realized by applying these projection display systems and screen structures, and the practical application thereof. In fact, in addition to the light distribution and practical application shown in fig. 1 and 2, other distributions of output light and other practical applications can be realized by applying these projection display systems and screen structures. Fig. 8a, 8b, 8c and 11 show four other examples.

As shown in fig. 8a, in this embodiment, the first output light and the second output light emitted from any point on the screen 801 have the same light distribution, and therefore, only the center point of the screen 801 is taken as an example for explanation. In the examples shown in fig. 1 and 2, the light emitted from any point on the screen has a particular direction, whereas in this example the light output from any point on the screen has a particular range of directions and not just a particular direction. For example, as shown in fig. 8a, the first output light is a beam of light with rays 811 and 813 as edge rays, and the second output light is a beam of light with rays 812 and 814 as edge rays. At this time, there are at least three regions in the horizontal viewing angle range, namely, a region L with rays 811 and 812 as edge rays, a region M with rays 812 and 813 as edge rays, and a region N with rays 813 and 814 as edge rays. It will be appreciated that an observer in region L can see the region of the first output light but not the second output light, an observer in region N can see the second output light but not the region of the first output light, and an observer in region M can see both the regions of the first and second output light. Therefore, the observer can view the image emitted by the first projection light source in the region L and can view the image emitted by the second projection light source in the region N; in the region M, the observer can see the above two images at the same time, and thus crosstalk is generated when the observer directly views the images. Thus, in the region M, the observer can wear 3D glasses, and the left and right lenses of the 3D glasses respectively filter light. For example, the left lens filters out the second output light and leaves the first output light transmission, and the right lens filters out the first output light and leaves the second output light transmission; or conversely, the left lens filters out the first output light and leaves the second output light for transmission, and the right lens filters out the second output light and leaves the first output light for transmission. In short, the left lens should filter out the image corresponding to the right eye and only allow the image corresponding to the left eye to transmit, and the right lens should filter out the image corresponding to the left eye and only allow the image corresponding to the right eye to transmit.

In current 3D displays, 2D images and 3D images can be selected and switched, but simultaneous presentation is not possible. This brings about several problems: (1) 3D glasses are generally expensive, and the glasses are not enough when being watched by a plurality of people; (2) not all people are accustomed to wearing 3D glasses; (3) the visual safety of 3D images has not been proven for children. The embodiment shown in fig. 8a successfully enables a 3D image and a normal 2D image to be displayed on one screen at the same time: a 2D image can be viewed while standing in regions L and N, and a 3D image can be viewed while standing in region M. The display method obviously brings brand new life experience.

In the example shown in fig. 8a, 3D glasses still have to be used for viewing in the area M, and the 3D glasses are inconvenient themselves and add extra cost to the 3D glasses. In the example shown in fig. 8b the use of 3D glasses is avoided. Take the left area 801c on the screen as an example. The first output light from the screen region 801c is edge light with rays 815 and 816, and the second output light from the screen region 801c is edge light with rays 817 and 818. It can be seen that the first output light and the second output light do not overlap. Assuming that there is an observer K at a distance from the screen, whose left eye is shown as 843a and whose right eye is shown as 843b, the design ray 816 is incident on the left eye 843a, while the design ray 817 is incident on the right eye 843 b. For other positions on the screen, the design is also based on the same principle, that is, the first output light and the second output light do not overlap, and two edge light rays close to each other are incident to the left eye 843a and the right eye 843b respectively. Thus, for the observer K, the left eye 843a can see the first output light at any point on the screen and cannot see the second output light, and the right eye 843b can see the second output light at any point on the screen and cannot see the first output light, so that the observer K sees a 3D effect image as long as the projection light source is matched to perform appropriate setting so that the image carried by the first output light corresponds to the left eye and the image carried by the second output light corresponds to the right eye.

Meanwhile, the observer 841 and the observer 842 can only see the first output light and the second output light, respectively, for each point on the screen, and thus see a 2D image.

fig. 8c is a variation of the example of fig. 8 b. In the example of fig. 8b, there is a gap between the first output light and the second output light at each point on the screen, in which gap neither the first output light nor the second output light is visible. Such a gap is for example between a first output light edge ray 816 and a second output light edge ray 817 on the screen area 801 c. In practical applications, there is a problem that the system has a high requirement for the position of the viewer K, and the viewer K cannot normally see 3D at a slight deviation. For example, if the viewer K is left, the left eye still sees the first output light, but the right eye falls into the aperture and does not see the second output light. Also, this places very high demands on the processing accuracy of the screen. Most preferably, as shown in FIG. 8c, edge rays 816 of the first output light and edge rays 817 of the second output light are closer together, both at the same time, near the position of the eyebrow center between the eyes of viewer K. Thus, the first output light also covers the left eye 843a, and the second output light also covers the right eye 843b, so that the 3D visual effect of the observer K is unchanged, but the requirements for the position of the observer K and the processing accuracy of the screen are greatly reduced, that is, the system fault tolerance is improved. Of course, the edge ray 816 of the first output light and the edge ray 817 of the second output light may coincide, and the system fault tolerance is the best.

The light distribution of the output light shown in fig. 8a to 8c differs from that shown in fig. 1 and 2 in that the output light for each position on the screen is no longer a ray of light of a specific direction, but a beam of light having a range of angles. However, in the descriptions of the embodiments shown in fig. 3a to fig. 7, the exit direction of the output light is controlled, that is, how to realize the output light of a specific direction of light, which can satisfy the output light distribution of the type represented in fig. 1 and fig. 2, but cannot directly realize the light distribution of the output light shown in fig. 8a to fig. 8 c.

In fact, on the basis of the technology that has been able to control the outgoing light in a specific direction (i.e. the solutions represented in fig. 3a to 7), it is easy to achieve the requirement that the outgoing light has a specific angular range. For example, a scattering layer may be used, which may be placed anywhere in the path of the light that is incident on the screen, or may be integrated with the screen, in the manner described and illustrated above. The scattering layer functions to scatter light in a specific direction into a scattered beam centered on the original specific direction, and the function of the scattering layer is shown in fig. 9. Fig. 9 is a diagram showing the relationship between the light intensity and the angle before and after the light is scattered, wherein a curve 911 is sharp and represents a light ray along a specific direction, a curve 912 of the light ray after being scattered to a certain degree is shown, and a light beam which is transmitted by taking the original light direction as the center is shown by 912, the angle range of the light beam depends on the degree of scattering, and the larger the scattering is, the larger the angle range is. It can be seen that by controlling the output light to exit in a specific direction, and by controlling the scattering degree of the scattering layer (for example, by controlling the parameters of refractive index, concentration and granularity of the scattering particles), the exit angle range of the final output light can be controlled.

There is a problem with the method of controlling the exit angle range of the output light by scattering light transmitted in a particular direction. The angular range of the scattered light distribution curve 912 can be controlled as shown in fig. 9, but the control of the curve shape (i.e., the light intensity distribution) is difficult in this range. For example, for light distribution 912, a pronounced scattered light distribution characteristic, i.e., a bell-shaped distribution, is present. There is a longer tail 912a at the two boundaries of the distribution. To achieve a sharp-edged light distribution, it is difficult to achieve this using the general scattering method.

one solution is to scatter light using micro-cylindrical mirror arrays or micro-lens arrays to obtain a scatter of a specific light intensity distribution, which is related to the surface type design of the micro-cylindrical mirrors or micro-lenses. This is prior art and will not be described here too much.

Another method for achieving a certain exit angle range of the output light is described below with reference to fig. 10a to 10 c. Referring back to fig. 5e, the method for controlling the angle of the outgoing light can control the outgoing directions of the first outgoing light 511a and the second outgoing light 512a by controlling the normal directions of the first micro-surface 504a and the second micro-surface 504 b. Fig. 10a to 10c show three examples of the improvement of fig. 5e as a prototype.

In fig. 10a, the triangle with dotted lines represents the microstructure in fig. 5e, wherein lines 504a and 504b represent the sectional lines of the original first and second facets in the left-right direction, respectively. In the present embodiment, a sectional line of the first micro-surface in the left-right direction is a curved line 1004a, and a sectional line of the second micro-surface in the left-right direction is a curved line 1005 a. It can be understood that the reflected light 1011a (i.e. the first output light) of the first input light 1021a after being incident on the first micro-surface 1004a no longer has only one exit direction, but light incident at different positions has different reflection directions; similarly, the reflected light 1012a (i.e., the second output light) of the second input light 1022a incident on the second micro-surface 1005a does not have only a single emission direction, but light incident on different positions has different reflection directions. Therefore, the light distribution of the output light can be controlled to a specific distribution by controlling the curved surface shapes of the first micro-surface and the second micro-surface of the microstructure. Specifically, the position of the first micro-surface 1004a near the top of the microstructure is substantially the same as the original first micro-surface 504a, and the light 1011a-1 reflected from this portion is in the same direction as the first output light 511a in fig. 5 e. The farther the first micro-surface 1004a is from the top of the microstructure, the more it is curved inward relative to the original first micro-surface 504a, which results in the outgoing angle of the light ray 1011a-2 reflected from the middle of the first micro-surface 1004a being further away from the normal direction of the screen than the light ray 1011a-1, and the outgoing angle of the light ray 1011a-3 reflected from the bottom of the first micro-surface 1004a being further away from the normal direction of the screen than the light ray 1011 a-2. It can be understood that since the first micro-surface 1004a is a gradually changing curved surface starting from the shape of the original first micro-surface 504a, the first output light 1011a is a light beam extending away from the normal of the screen and having the original first output light 511a as an edge light. The second micro-surface 1005a is designed in the same manner. This method is suitable for screen designs that produce the light distributions of fig. 8a to 8 c; it is noted that this method is particularly suitable for the case of fig. 8b and 8c where the angle requirement for at least one edge ray (e.g., edge rays 816 and 817) is high.

as is clear from the above description, the distribution of the first output light 1011a is related to the shape of the first micro-surface 1004a, and the distribution of the first output light 1011a can be controlled according to the shape of the first micro-surface 1004a by appropriately designing the shape. Likewise, the design of the shape of the second micro-facet 1005a may control the distribution of the second output light 1012 a.

in this example, the first and second micro-surfaces 1004a and 1005a are continuously varied, but in reality, a continuous curved surface is not easy to process, and thus can be approximated using a planar mosaic in which the normal directions of a plurality of segments are continuously varied.

The example of fig. 10b serves the same purpose as that of fig. 10a, except that the first facets 1006a are not continuous, but rather are saw-toothed. Each sawtooth has a face facing the input light, the normal direction of the faces being continuously varied to achieve a specific distribution of the output light.

The example shown in fig. 10c is the same as that of fig. 10a, but in the example shown in fig. 10c, the original microstructure (triangle shown by dotted line) is replaced by a plurality of sub-microstructures, each sub-microstructure can control the direction of the output light by means of the reflection of the two micro-surfaces to the input light, but the direction of the output light generated by each micro-surface is different and continuously changed, so that the specific distribution of the output light can be realized.

It is understood that fig. 10a to 10c are modified with respect to the microstructure shown in fig. 5e, but this is only an example, and the same method can be applied to other embodiments of the present invention, as long as the direction of the output light is controlled by controlling the shapes of the microstructure, the prism unit, the reflection unit, etc. in this embodiment, the method of modifying fig. 10a or 10b to fig. 5e can be further applied to control the distribution of the output light by changing the surface shapes of the microstructure, the prism unit, and the reflection unit, or the method of modifying fig. 10c to fig. 5e can be further applied to control the distribution of the output light by using a plurality of different sub-microstructures, sub-prisms, and sub-reflection units as a whole. Further, the improved methods of fig. 10a to 10c may also be combined with scattering to achieve angular control of the output light.

Fig. 11 shows another example of output light distribution, which is a modification of fig. 2. In the light distribution shown in fig. 2, the first output light is incident on the left eye 241 of an observer, and the second output light is incident on the right eye 242 of the same observer; this makes it impossible to view a 3D image in any position other than this observer. The light distribution shown in fig. 11 solves this problem by enabling a 3D image to be seen in two orientations in front of the screen 1101. In the projection display system of fig. 11, there are two observers, the left and right eyes of the first observer are denoted as 1141 and 1142, respectively, and the left and right eyes of the second observer are denoted as 1143 and 1144, respectively. The first output light emitted from any position on the screen 1101 is two separate beams, which are respectively incident on the left eyes of the first observer and the second observer, and the second output light emitted from any position on the screen 1101 is also two separate beams, which are respectively incident on the right eyes of the first observer and the second observer. So that both the first viewer and the second viewer can see the 3D image.

As can be seen from the above description, the outgoing light at any position on the screen 201 in fig. 2 is a light ray or light beam with a specific outgoing direction, and in contrast, the outgoing light at any position on the screen 1101 in fig. 11 is two separate light rays or light beams with different specific outgoing directions. To achieve this effect of the screen 1101, only the screen technology described above needs to be modified.

still taking the embodiment of fig. 5e as an example, the screen structure of fig. 5e is modified to implement the function of having two separate light rays with different specific outgoing directions. Fig. 12a and 12b are examples of two modifications to fig. 5 e. In FIG. 12a, the first facet becomes a mosaic of two patch planes 1204a-1 and 1204a-2 with different normal directions. The first input light 1221a is incident on the surfaces of the patch planes 1204a-1 and 1204a-2, and the first output light 1211a-1 exiting from the surface thereof may be incident on the left eye 1141 of the first observer by controlling the normal direction of the patch plane 1204a-1, while the first output light 1211a-2 exiting from the surface thereof may be incident on the left eye 1143 of the second observer by controlling the normal direction of the patch plane 1204 a-2. Similarly, the second micro-surface 1105a is formed by splicing two small planes with different normal directions, and the second input light 1222a is incident on the two small planes; the formation of two separate second output lights 1212a incident on the first observer's right eye 1142 and the second observer's right eye 1144, respectively, can be controlled by controlling the normal direction of the two patch planes.

the screen microstructure shown in fig. 12b is actually a variation of fig. 12 a. The two facet planes 1204a-1 and 1204a-2 of the first facet 1204a in fig. 12a are respectively combined with the two facet planes of the second facet 1205a to form two independent sub-microstructures adjacent to each other, each of which has the same plane facing the first input light as the facet planes 1204a-1 and 1204a-2, respectively. It will be appreciated that these sub-microstructures as a whole can achieve the same technical effect as the screen microstructure of figure 12 a.

it will be appreciated that fig. 12a and 12b are only exemplified with two viewers in front of the screen. To sum up, if there are n observers, each micro-surface needs to be formed by splicing n small planes with different normal directions for the screen microstructure of fig. 12a, and the micro-surfaces respectively correspond to the n observers; for the screen microstructure of fig. 12b, n adjacent sub-microstructures with different shapes are required, and the micro-surface of each microstructure corresponds to n observers.

It is understood that fig. 12a and 12b are modified with respect to the microstructure shown in fig. 5e, but this is only an example, and the same method can be applied to other embodiments of the present invention, as long as the direction of the output light is controlled by controlling the shapes of the microstructure, the prism unit and the reflection unit in this embodiment, the method of modifying the structure shown in fig. 12a to 5e can be further applied to control the distribution of the output light by changing the shapes of the microstructure, the prism unit and the reflection unit, or the method of modifying the structure shown in fig. 12b to 5e can be further applied to control the distribution of the output light by using a plurality of different sub-microstructures, sub-prisms and sub-reflection units as a whole.

as far as here we can make a summary of the distribution of the output light protected by the present invention. Fig. 1 and 2 illustrate the simplest form of the distribution of the output light, that is, the first output light and the second output light emitted from any point on the screen are respectively a beam in a specific direction. Fig. 8a to 8c illustrate another form of output light distribution, that is, the first output light and/or the second output light emitted from any point on the screen has a specific angle range, and it is particularly preferable that the light intensity distribution of the output light is controllable in the angle range. Fig. 12a and 12b illustrate a third form of output light distribution, namely, the first output light and the second output light emitted from any point on the screen are n (n is not less than 2) separate light beams emitted in different directions.

These three output light distribution patterns are all possible, as has been described in detail in the embodiments above. Moreover, the three output light distribution forms have important application value. It will be appreciated that the second and third output light profiles may be mixed, i.e. the first output light and/or the second output light may also be n (n is not less than 2) separate sub-beams, each sub-beam having a specific angular range. The practical effect of using the second and third output light distributions in combination can be obtained: two or more positions in front of the screen have 3D visual effects, while other positions can view 2D images simultaneously. A summary of the output light distributions is that the output light distributions need to satisfy the following conditions, and it is within the scope of the present invention:

when an observer watches at least one point A on the screen, a first visual angle range and a second visual angle range which are not overlapped with each other necessarily exist in the whole horizontal visual angle range, the first output light can be seen and the second output light cannot be seen in the first visual angle range, and the second output light can be seen and the first output light cannot be seen in the second visual angle range.

In the above description, two output lights are taken as an example, and more output lights can be actually realized according to the method of the present invention. Those skilled in the art can easily deduce the design method of the projection display system and the screen for obtaining multiple output lights according to the description of the present invention.

the above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. A screen for receiving input light projected thereon, characterized by:

The input light comprises first input light and second input light emitted from a first projection light source and a second projection light source which are different in position, and images carried by the first input light and the second input light are different;

the screen comprises a microstructure layer, wherein the microstructure layer comprises a first micro surface and a second micro surface; the first micro surface faces the first input light and projects the first input light out in a reflection mode to form first output light of the screen, and the second micro surface faces the second input light and projects the second input light out in a reflection mode to form second output light of the screen;

The emergent directions of the first output light and the second output light are different, so that when at least one point A on the screen is watched, a first visual angle range and a second visual angle range which are not overlapped with each other inevitably exist in the whole horizontal visual angle range, the first output light can be seen and the second output light cannot be seen in the first visual angle range, and the second output light can be seen and the first output light cannot be seen in the second visual angle range.

2. a screen according to claim 1 wherein the first range of viewing angles is within a range of viewing angles from a line drawn from point a on the screen to the centre of the viewer's eyebrow to the left, and the viewer's left eye falls within the first range of viewing angles; the second visual angle range is positioned in the visual angle range right to the connecting line direction from the point A to the eyebrow center of the observer on the screen, and the right eye of the observer is positioned in the second visual angle range.

3. A screen as recited in claim 1, further comprising a third range of viewing angles between the first range of viewing angles and the second range of viewing angles throughout the horizontal range of viewing angles, wherein the first output light and the second output light are viewable concurrently within the third range of viewing angles.

4. A screen according to any one of claims 1 to 3, characterized in that said first micro-surface is not facing said second input light, said second micro-surface being not facing said first input light.

5. a screen according to any one of claims 1 to 3 wherein said first and second facets have reflective layers attached or coated thereon, wherein the first input light is reflected by the first facet to form the first output light and the second input light is reflected by the second facet to form the second output light.

6. A screen according to any one of claims 1 to 3, characterized in that:

The micro-structure layer is a prism array which is arranged side by side and extends along a specific direction, and the first micro surface and the second micro surface are two upper surfaces of the prism facing to input light;

or, the microstructures in the microstructure layer are arranged in an array or irregularly, the microstructures are irregular polyhedrons, the front surface of a first micro surface of each microstructure faces to the first input light, and the front surface of a second micro surface of each microstructure faces to the second input light.

7. A screen according to any one of claims 1 to 3, characterized in that:

The microstructure layer comprises at least one microstructure, and a first micro surface and/or a second micro surface of the microstructure are curved surfaces or formed by splicing a plurality of small planes with different normal directions, so that the direction distribution of first output light and/or second output light emitted from the microstructure is preset distribution;

or the microstructure layer comprises n adjacent sub-microstructures, n is greater than or equal to 2, and the normal directions of the corresponding first micro-surface and/or second micro-surface of the sub-microstructures are different, so that the direction distribution of the first output light and/or second output light projected by the n sub-microstructures as a whole is preset distribution.

8. A screen according to any one of claims 1 to 3, further comprising a scattering layer independent of or part of other elements of the screen; the scattering angle of the scattering layer in the horizontal angular direction is smaller than the scattering angle in the vertical angular direction.

9. A screen as recited in claim 8, wherein the scattering layer comprises a plurality of horizontally extending cylindrical surfaces or columns arranged in an array or in a stray arrangement.