CN1078950C - Fresnel lens and liquid crystal display device - Google Patents

Abstract

A display device includes a liquid crystal display panel, an array of converging transmissive elements for forming a real upright image, and a Fresnel lens for magnifying the image. The structured surface of the fresnel lens is disposed on the light incident side. The structured surface includes periodic ridges with flat tops and sloped surfaces. A light-shielding layer is provided on top of the flat to eliminate double images.

Description

Fresnel lens and liquid crystal display device

The present invention relates to a Fresnel lens having a light-shielding layer and a display device such as a liquid crystal display device including a magnifying Fresnel lens.

Liquid crystal display devices can have a thinner structure and have been used in many applications. Recently, large-screen projection type liquid crystal display devices have been developed. A typical projection liquid crystal display device includes a projection lens for projecting a magnified image onto a screen. In addition, optical elements other than projection lenses may be used to magnify the image.

For example, Japanese Unexamined Patent Publication (Kokai) No. 5-188340 discloses a projection type liquid crystal display device including a liquid crystal display device, a Fresnel lens for enlarging an image generated by the liquid crystal display device, and a screen. In this case, the liquid crystal display device also includes an array of converging transmissive elements and a screen. Each array of converging transmission elements is adapted to form an upright real image the same size as the object, and each Fresnel lens is used to magnify the image from the array of converging transmission elements.

These converging transmission elements are made of plastic or glass in the form of transparent rods with a diameter of 1 mm to 2 mm, so that the refractive index of each transparent rod changes along its radial direction. By appropriate selection of their length and refractive index profile, individual converging transmissive elements can be used to form erect real images having the same size as the object. A plurality of converging transmissive elements, arranged close to each other, with end surfaces of these elements arranged in a row or in a plane, thereby forming a row or an array of converging transmissive elements. An array of converging transmission elements can be used as an imaging device for producing an upright real image having the same size as the object. Compared with the usual spherical lens, the imaging device using this converging transmission element array has some advantages, that is, the focal length is very short, and the optical performance is uniform on the row or plane, so that there is no need to adjust the distance between the lenses. adjust.

However, when such an array of converging transmission elements is used as an imaging device, the magnification of the image cannot be changed, although the magnification of each converging transmission element can be changed by changing the length of the elements. This is due to the magnified images produced by the individual converging transmissive elements, one on top of the other, being inconsistently superimposed in the array and not forming a proper image. Therefore, the converging transmission element array can only be used as a full-scale imaging device, and a magnification device needs to be provided outside the converging transmission element array.

Japanese Examined Patent Publications (Kokoku) No.58-33526 and No.61-12249 disclose a kind of imaging device, it comprises the converging transmission element array and the convex lens and the concave lens as the magnifying device, these lenses are arranged on the converging transmission through the incident or outgoing side of the element array. The convex or concave lens can be a single lens or a compound lens composed of multiple lens elements to achieve the desired magnification. However, when such an imaging device is used in a liquid crystal display device together with a magnifying device, there arises a problem that the resolution of the lens varies from the central portion to the peripheral area.

It has been found that good images can be obtained if the resolution MTF is greater than 50% at 4 (1 p/mm), ie four pairs of white and black dots per millimeter. However, in the prior art described above, it is generally difficult to obtain an image having a resolution MTF greater than 50%. Light needs to pass through the peripheral area of the LCD panel at an angle of about 10 degrees relative to the normal of the LCD panel to ensure a resolution MTF greater than 50%. The smaller the angle in the peripheral region, the smaller the magnification of the device. As a result, in the case of employing a convex lens or a concave lens together with an array of converging transmission elements, it is impossible to realize a liquid crystal display device with a thin structure, although the array of converging transmission elements itself can provide a liquid crystal display device with a thin structure.

Therefore, there is a need for an amplifying element which can be used with an array of converging transmissive elements and which can realize a liquid crystal display device having a thin structure. In the aforementioned Japanese-Unexamined Patent Publication (Kokai) No. 5-188340, a Fresnel lens employed with an array of converging transmission elements is disclosed, but the use of such a Fresnel lens is not disclosed in this prior art Way. The inventors have recently found that good results can be obtained if a Fresnel lens is used as the magnifying element.

Further, in the liquid crystal display device, there is a problem that the brightness of an image on the peripheral area of the screen is reduced with respect to the brightness of the image on the central area of the screen.

The object of the present invention is to provide a Fresnel lens which has such a construction that light is incident on its structured surface.

Another object of the present invention is to provide a display device with a thin structure by properly arranging Fresnel lenses.

Another object of the present invention is to provide a display device in which the brightness of the screen is improved.

According to one aspect of the present invention, there is provided a Fresnel lens comprising a body having a planar surface and a structured surface with periodic ridges. Each of the ridges includes a flat top extending parallel to the top of the flat surface and at least one inclined surface extending from the flat top to the flat surface, and a light shielding layer disposed on the flat top of each ridge .

The flat top preferably has a width that varies according to the location of the ridge. In this case, at least one of the sloped surfaces comprises a misleading main sloped surface which is arranged on one side of the flat roof and is suitably designed so that the light is mainly from the main sloped A secondary inclined surface on the other side from the surface, incident on the body.

The width of the flat top is preferably determined by the following relationship: $d=p\frac{\mathrm{the\; tan}r}{\mathrm{the\; tan}(90-\mathrm{\θ}1)+\mathrm{the\; tan}r}\×\[1-\frac{\mathrm{the\; tan}\mathrm{\θ}2}{\mathrm{the\; tan}r}\]---\left(1\right)$ where d is the width of the flat top, p is the pitch of the ridges, r is the angle between the chief ray incident on the body from the main inclined surface and the axis, _θ is the angle of the main inclined surface relative to the flat surface, and _θ2 is the angle of the secondary inclined surface with respect to the axis.

According to another aspect of the present invention, there is provided a display device comprising: at least one image modulator, an array of converging transmissive elements receiving light from said at least one image modulator to form a vertical solid image; a Fresnel lens comprising a body with a planar surface and a structured surface with periodic ridges, the Fresnel lens being suitably arranged so that light is incident from an array of converging transmission elements to a Fersnel lens on the structured surface of the Fresnel lens; and, a screen that receives light from the at least one image modifier through the array of converging transmission elements and the Fresnel lens.

Each ridge preferably includes a flat top and at least one inclined surface, the flat top extending parallel to the flat surface, the inclined surface extending from the flat top toward the flat surface; and on the flat top of each ridge there is provided a shading layer.

These flat crests preferably have a width that varies according to the location of the ridge. The at least one inclined surface preferably comprises: a main inclined surface, which is arranged on one side of the flat top and is suitably designed so that light is mainly incident on the body from the main inclined surface; and, a secondary inclined surface, It is arranged on the different side of the flat top from the main inclined surface.

The at least one image modulator preferably includes a plurality of liquid crystal display panels, and the array of converging transmissive elements and Fresnel lenses are disposed on each liquid crystal display panel. Preferably, four groups of liquid crystal display panels, convergent transmission element arrays and Fresnel lenses are arranged, and each group is arranged in each quarter of the rectangular area. The total display area of the screen is larger than that of a group of liquid crystal displays. The display area required by the panel, the array of converging transmissive elements, and the Fresnel lens to receive the image is four times larger.

On or near the screen and between adjacent groups of liquid crystal display panels, arrays of converging transmissive elements and groups of Fresnel lenses, spacers are provided to prevent light from being scattered from one group into an adjacent group.

The screen preferably has a predetermined display area, and the at least one image modulator has a main display area and a peripheral compensation area suitably arranged so that the main display area is at a predetermined An image is formed on the display area, and an image is formed in the peripheral compensation area outside the predetermined display area through the converging transmission element array and the Fresnel lens. The peripheral compensation area of said at least one image modulator is preferably controlled to provide an image substantially identical to an image provided from the main display area of the at least one image modulator in the vicinity of the peripheral compensation area Part of it is roughly the same.

Between two adjacent liquid crystal display panels, said peripheral compensation area of one liquid crystal display panel is preferably controlled to provide an image which is different from the image provided from the main display area of the adjacent liquid crystal display panel. A part of the image is substantially the same, the liquid crystal display panel is in the vicinity of the peripheral compensation area of said one liquid crystal display panel.

According to another aspect of the present invention, a display device is provided, which includes: at least one image modulator; an optical lens for amplifying the image output of the at least one image modulator; a screen for receiving The optical lens and the image from the at least one image modulator, the screen has a predetermined display area, and the at least one image modulator has a main display area and a peripheral compensation area suitably set so that the main The display area forms an image on the predetermined display area through the optical lens, and the peripheral compensation area forms an image outside the predetermined display area through the optical lens.

The present invention can be better understood from the following description of the preferred embodiment when taken in conjunction with the accompanying drawings. In the attached picture:

1 is a cross-sectional view of a liquid crystal display device according to an embodiment of the present invention;

Fig. 2 is a plan view showing the arrangement of four liquid crystal display panels of Fig. 1;

Figures 3A to 3C show features of a converging transmission element of Figure 1;

Figure 4 shows the propagation of light in a converging transmissive element;

Figure 5 shows the formation of an upright real image, which has the same size as the object;

FIG. 6 is a schematic perspective view of the convergent transmission element array of FIG. 1;

Figure 7 shows how the imaging surface and resolution are reduced;

Fig. 8 is a lateral sectional view of the Fresnel lens of Fig. 1;

Fig. 9 is a partial plan view of the Fresnel lens of Fig. 8;

Figure 10 is a transverse cross-sectional view of a portion of the Fresnel lens of Figures 8 and 9;

Fig. 11 is the lateral sectional view of traditional Fresnel lens;

Figure 12 is similar to Figure 10, but includes several parameters for calculating the width of the opacifying layer on top of the flat top of the ridge of the structured surface of the Fresnel lens;

Fig. 13 is a plan view of a modified liquid crystal display panel;

Figure 14 shows the images produced by the main display area and the peripheral compensation area of the liquid crystal display panel;

Figure 15 shows the images produced on the screen by two adjacent liquid crystal display panels;

Figure 16 shows the image produced by the main display area, and the image of the peripheral compensation area of the liquid crystal display panel of Figure 15;

Fig. 17 is a schematic transverse cross-sectional view of a liquid crystal display device similar to the arrangement of Fig. 13;

18 is a transverse cross-sectional view showing the path of light from the main display area and peripheral compensation area to the screen;

Figure 19 is a plan view showing a pixel on the screen;

Figure 20 is a plan view of several pixels of an image on the screen; and

Fig. 21 shows how the image brightness is reduced in the peripheral area of the screen.

1 and 2 show a liquid crystal display device 10 according to the present invention. The liquid crystal display device 10 includes four liquid crystal display panels 12 arranged in quarters of one rectangular area. Each liquid crystal display panel 12 includes an effective display area 12a and a non-display area 12b positioned around the effective display area 12a; of. Therefore, no image is formed on the non-display area 12b, and if the four liquid crystal display panel 12 is viewed directly, a discontinuous image is formed. This embodiment realizes continuous multiple display from discontinuous images of four liquid crystal display panels 12 by providing magnifying elements.

In FIG. 1 , a liquid crystal display device 10 includes a backlight 14 on the rear side of panels 12 , and an array of converging transmissive elements 16 disposed on the front side of each panel 12 . The area of each converging transmission element array 16 is larger than the area of the active display area 12a and smaller than the total area of the panel 12 including the non-display area 12b. Each converging and transmitting element array 16 can form an upright real image with the same size as the object, that is, the image produced by the liquid crystal display panel 12 .

The liquid crystal display device 10 includes Fresnel lenses 18 respectively disposed on the output side of the converging transmission element array 16 . Each Fresnel lens 18 comprises a transparent body having a planar surface 18a and a shaped surface 18b of serrated cross-section with concentric periodic ridges 19 as shown in FIGS. 8 and 9 . In the present invention, the Fresnel lens 18 is properly arranged so that light is mainly incident on the shaping surface 18b of the Fresnel lens 18 . In the arrangement in FIG. 1 , the shaping surface 18b faces the array 16 . The flat surface 18a is thus arranged on the light exit side.

The liquid crystal display device 10 also includes a screen 22 having a screen Fresnel lens 20 on the front side of the Fresnel lens 18 . The light beams emitted from the Fresnel lenses 18 travel toward the screen 22 in a diverging manner so that the light beams emitted from adjacent Fresnel lenses 18 meet on the screen 22 without discontinuity. Therefore, a person viewing the screen 22 cannot see the non-display area 12b of the liquid crystal display panel 12. The liquid crystal display panel 12 is an example of an image modulating device, but other types of image modulating devices (which combine light) may also be used.

The array 16 includes a plurality of converging transmissive elements 16a, and features of one converging transmissive element 16a are shown in Figures 3A to 3C. The converging transmissive element 16a is made of plastic or glass in the form of a transparent rod with a diameter of 1 mm to 2 mm. The refractive index within the volume of element 16a changes radially, as shown in Figure 3C. The distribution of the refractive index n(r), expressed by the following formula:

n(r)=n ₀ (1−g ² r ² /2) where r is the distance from the longitudinal axis, n ₀ is the refractive index on the longitudinal axis, and g is the distribution constant of the refractive index.

The light enters from the end surface of the converging transmissive element 16a, and while passing through the converging transmissive element 16a, the light is bent toward its part with a higher refractive index, so that the light travels along a periodic serpentine path, as shown in FIG. 4 . The period P is represented by P=2/π/g. If the length Z of the converging transmission element 16a is selected according to the relationship P/2<Z<3P/4, an upright real image having the same size as the object can be formed, as shown in FIG. 5 . The distance L is the distance between the object and the image.

FIG. 6 shows a case where the converging transmissive elements 16 a are arranged in close proximity to each other and their end surfaces are arranged in a line or in a plane, thereby forming the array 16 . An upright real image having the same size as the object can be formed by means of the array 16 . An imaging device employing an array 16 of converging transmissive elements 16a has the advantages of a very short focal length and uniform optical properties in a line or plane. However, the array 16 of converging transmissive elements 16a cannot change the magnification of the image relative to the object, although the magnification of individual converging transmissive elements 16a can be changed when the length of the elements 16 is changed. This is due to the fact that the magnified images formed by the individual converging transmissive elements 16a are inconsistently superimposed on each other on the array 16 and no normal image is formed on the array 16. Therefore, the array 16 of converging transmissive elements 16a can only be used as a full-scale imaging device, and the Fresnel lens 18 is used as the magnifying device.

In this embodiment, the effective area 12a of the liquid crystal display panel 12 is 211.2mm * 158.4mm, and the required magnification (the sum of the area of the effective area 12a and the area of the invalid area 12 divided by the area of the effective area 12a) is 1.09. For the converging transmissive element 16a, the refractive index n is 1.507, the distribution constant g of the refractive index is 0.1847, the length Z is 18.89 mm, and the diameter is 1.18 mm. The magnifying Fresnel lens 18 is made of acrylic with a refractive index of 1.494 and has a radius of curvature in which the central curvature (cuy) is -0.00813668, the second order constant is -0.775202×10 ^-8 , and the third order constant is 0.318549 ×10 ^-13 , the fourth-order constant is -0.720974×10 ^-19 , and the fifth-order constant is -0.717576×10 ^-25 . The angle between the light emitted from the outermost peripheral position of the Fresnel lens 18 and the normal of the Fresnel lens 18 is 28.3 degrees. The screen Fresnel lens 20 is used to converge the beams emitted from the magnifying Fresnel lens 18 at various angles with respect to the parallel beams, and is made of MS with a refractive index of 1.537. The resolution MTF in this example is shown in the table below: AEP(°) MTF(%) 2(1p/mm) 4(1p/mm) 28.3 89.7 64.0

In another embodiment, the shape of the shaping surface 18b of the Fresnel lens 18 is changed such that the angle (AEP) of light emitted from the outermost peripheral portion of the Fresnel lens 18 is changed. The resolution MTF was checked while varying the angle (AEP). In this example, the converging transmissive element 16a has a refractive index n of 1.505, a distribution constant of the refractive index g of 0.1847, a length Z of 18.895 mm, and a distance L of 20 mm. The Fresnel lens 18 has a thickness of 2 mm and a refractive index of 1.494. A Fresnel lens 18 is arranged in contact with the array 16 of converging transmissive elements 16a. In this setup, the curvature of the Fresnel lens 18 is set to be parabolic such that a beam of light parallel to the optical axis of the Fresnel lens 18 (called the main beam) emerges from the Fresnel lens 18 at an angle (AEP) The outermost peripheral portion of , and the focus is on the position of the line passing through the Fresnel lens 18 . The resolution MTF in this example, is shown in the table below. It should be noted that the shaped surface 18b is located on the light incident side, and the flat surface 18a is located on the light exit side. AEP(°) MTF(%) 2(1p/mm) 4(1p/mm) 10 99.7 98.9 20 98.1 92.7 30 88.7 61.1 40 88.9 61.5

As can be seen from the table, even at an angle (AEP) of 40 degrees, the obtained MTF values are satisfactory. Note that this result is obtained in an arrangement in which the shaped surface 18b is located on the light incident side and the flat surface 18a is located on the light exit side.

It can be said that the image is basically formed on a plane, however, the imaging surface is somewhat curved. Therefore, if the focal point is at a position on a straight line passing through the center of the Fresnel lens 18, the MTF value at peripheral positions will be reduced. In the above table, the MTF values at (AEP) of 10 to 30 degrees are obtained when the focal point is at a position on a straight line passing through the center of the Fresnel lens 18, but at an angle of (AEP) of 40 degrees The MTF value at is obtained when the focus is adjusted so that the MTF value at the center of the Fresnel lens 18 is equal to the MTF value at the outermost peripheral portion of the Fresnel lens 18 .

The following table shows the best test results of the resolution MTF obtained when the flat surface 18a is on the light incident side and the shaped surface 18b is on the light exit side, and other conditions are the same as in the above examples. This result should be compared with the resolution MTF obtained when the shaped surface 18b is on the light incident side and the flat surface 18a is on the light exit side. AEP(°) MTF(%) 2(1p/mm) 4(1p/mm) 10 95.8 84.0 12 90.8 65.0 13 86.9 55.4 14 81.6 41.5 15 76.1 28.8 20 26.6 5.5

According to the evaluation by observing the screen, it has been found that the produced image is good when the MTF value is greater than 50% at 4 (1p/mm). Therefore, in this comparison test, it can be said that an angle (AEP) equal to or less than 13 degrees is satisfactory, but the curvature of the Fresnel lens is limited to this range.

The present inventors made further attempts to analyze the reason why the resolution MTF decreases when the flat surface 18 a is on the light incident side and the shaped surface 18 b is on the light exit side.

As shown in FIG. 7, it has been found that the focal length of the Fresnel lens 18 becomes shorter as the position moves from the center of the Fresnel lens 18 toward its periphery, and the imaging surface is distorted relative to the screen 22, As shown by the dotted line F. In FIG. 7, the array 16 of converging transmissive elements 16a and the Fresnel lens 18 are shown, but the Fresnel lens 18 is arranged such that the shaping surface 18b is on the light exit side.

In the analysis of the distorted image surface, attention is paid to the angle (AIM) between the beams 30 and 31, which are on either side of the main beam and which are at the same angle with the main beam. The angle (AIM) of the light beams 30 and 31 becomes smaller when the light is incident on the Fresnel lens 18, and becomes larger when the light exits the Fresnel lens 18, regardless of One surface is located on the light incident side. This tendency is enhanced as the angle between the incident or combined light and the entry or exit surface increases, ie the tendency is stronger for the shaped surface 18b. Therefore, the angle (AIM) between the light beams 30 and 31, in an arrangement where the light exits the forming surface 18b, becomes larger, and the image is formed farther from the screen 22 as the angle (AIM) is larger. position, thus reducing the resolution MTF. In the case where the light exits from the flat surface 18a, the angle (AIM) does not become so large, and in this case, an image can be formed on the screen 22.

FIG. 10 shows a detail of the Fresnel lens 18 of FIG. 1 . As mentioned above, the Fresnel lens 18 has a planar surface 18a and a shaped surface 18b with concentric periodic ridges 19 thereon. Each ridge 19 includes a flat top 19a extending parallel to the flat surface 18a and an inclined surface 19b extending from the flat top 19a toward the flat surface 18a. On the side of the flat top 19a opposite to the inclined surface 19b, a smaller surface 19c is provided. On the flat top 19a of each ridge 19, a light shielding layer 19d is provided. The light-shielding layer 19d can be easily formed by printing because the flat top 19a is parallel to the flat surface 18a.

FIG. 11 shows a conventional Fresnel lens 18 with ridges 19 . It should be understood that the flat top 19a of FIG. 10 is formed by cutting off the top of the ridge 19 of FIG. 10 . In the conventional Fresnel lens 18 shown in FIG. 10, there is a problem that scattered light beams produce ghost images. That is, if light S is incident on the inclined surface 19b at a position near the smaller surface 19c, the light ray S is reflected by the smaller surface 19c and changes its path uncontrollably, thereby causing a ghost image. The light-shielding layer 19d is provided to solve this problem.

As can be seen from FIG. 8, the shape or slope of the ridge 19 varies according to the position on the ridge 19, and the width of the flat top 19d preferably varies according to the position on the ridge 19.

As shown in FIG. 12 , surface 19c may be inclined relative to flat surface 18a to make Fresnel lens 18 . As will be explained, the main inclined surface 19b, which is arranged on one side of the flat top 19a, is designed such that light is mainly incident on the body of the Fresnel lens 18 from the main inclined surface 19b, and the secondary inclined surface 19c is It is provided on the other side of the flat top 19a opposite to the main inclined surface 19b.

The width of the flat top 19a is preferably determined by the following relationship: $d=p\frac{\mathrm{the\; tan}r}{\mathrm{the\; tan}(90-\mathrm{\&theta;}1)+\mathrm{the\; tan}r}\&times;\&lsqb;1-\frac{\mathrm{the\; tan}\mathrm{\&theta;}2}{\mathrm{the\; tan}r}\&rsqb;---\left(1\right)$ where d is the width of the flat top 19a, p is the pitch of the ridges 19, r is the angle relative to the axis of the chief ray incident on the body from the main sloped surface 19b, and _θ is the angle of the main sloped surface 19b relative to the flat surface 18a angle, and θ ₂ is the angle of the sub-inclined surface 19c with respect to the axis of the Fresnel lens 18.

13, 17 and 18 show a modified liquid crystal display device 10 comprising four sets of liquid crystal display panels 12, an array 16 of converging transmissive elements 16a and Fresnel lenses 18, and a screen 22. These four groups are arranged on respective quarters of the rectangular area. The total display area of the screen 22 is four times greater than the predetermined display area 22p required to receive images from the set of liquid crystal display panels 12, array 16 of converging transmissive elements 16a and Fresnel lenses 18. That is, the screen 22 has a predetermined display area 22 p for each liquid crystal display panel 12 .

On or near the screen 22 between two adjacent groups of liquid crystal display panels 12, the array 16 of converging transmission elements 16a and the Fresnel lens 18, a partition 26 is arranged to prevent light from being scattered from one group to the adjacent one. in the group.

Each liquid crystal display panel 12 includes an effective display area 12a and a non-display area 12b around the effective display area 12a, as described in conjunction with FIG. 2 . The effective display area 12a is divided into a main display area 12x and a peripheral compensation area 12y. The main display area 12x forms an image on a predetermined display area 22p through the array 16 of converging transmissive elements 16a and the Fresnel lens 18. The peripheral compensation area 12y, through the array 16 of converging transmissive elements 16a and the Fresnel lens 18, forms an image just outside the intended display area 22p. That is, the peripheral compensation area 12y does not contribute to the formation of an actual image on the screen 22, but compensates for loss of brightness in the peripheral area of the liquid crystal display panel 12. As an example, the active display area 12a includes 640x480 pixels, and the main display area 12x includes 620x465 pixels.

As shown in FIG. 14, the peripheral compensation area 12y _of the liquid crystal display panel 12 is controlled to provide an image _I1 which is consistent with the image from the main display area 12x of the liquid crystal display panel 12 near the peripheral compensation area 12y. Like part I ₁ is basically the same.

As shown in FIGS. 15 and 16, the peripheral compensation area 12y of the liquid crystal display panel ₁₂ is controlled to provide an image I ₂ which is consistent with the image from the main display area 12x of the adjacent liquid crystal display panel 12. Like the part _I2 is basically the same, and the main display area 12x is located near the peripheral compensation area 12y of the liquid crystal display panel 12 .

FIG. 19 shows an element 50 of the image on the screen 22. As shown in FIG. The element 50 should be a point on which several beams are focused, but in practice, due to the aberrations of the magnifying Fresnel lens 18, the beams will be spread over a certain area 51 . Therefore, the brightness of the element 50 is reduced. Figure 20 shows several elements 50, 50a, 50b, 50c, and 50d, and their interspersed areas 51, 51a, 51b, 51c, and 51d. Element 50 receives light from other elements 50a, 50b, 50c and 5Od, and the brightness of element 50 will be compensated to some extent. FIG. 21 shows the peripheral portion of the screen 22 when the peripheral compensation area 12y is not provided. Wherein there are several elements 50, 50a, 50b, 50c and 50d on the peripheral portion of the screen 22, and their scattered areas 51, 51a, 51b, 51c and 51d, but the brightness of these elements is not compensated, because in the predetermined There is no unnecessary light component outside the display area 22p.

As shown in FIG. 18, the peripheral compensation area 12y generates light outside the predetermined display area 22p, but does not contribute to the formation of an actual image, but the light emitted from the peripheral compensation area 12y may include scattered light components—the scattered light The composition compensates for the decrease in brightness on the peripheral portion of the screen 22 .

Claims (20)

1. a Fenier lens comprises a body, and this body has a flat surfaces and the surface with structure that has periodic ridge;

Each ridge comprises a smooth top and at least one inclined surface, and extend substantially abreast with this flat surfaces on the top that this is smooth, and this inclined surface from this smooth top towards this flat surfaces extension, the width on wherein smooth top changes according to the position of ridge; And

Be arranged on the light shield layer on the smooth top of each layer.

2. according to the Fenier lens of claim 1, wherein at least one inclined surface comprise the main inclined surface on the side that is arranged on smooth top and be arranged on smooth top and opposite side that main inclined surface is opposing on secondary inclined surface.

3. according to the Fenier lens of claim 2, the width on wherein smooth top is determined by following relation: $d=p\frac{\tan r}{\tan (90-\mathrm{\&theta;}1)+\tan r}\&times;\&lsqb;1-\frac{\tan \mathrm{\&theta;}2}{\tan r}\&rsqb;---\left(1\right)$ Wherein d is the width on smooth top, and p is the spacing of ridge, and r incides chief ray on the body with respect to the angle of axis, θ from main inclined surface ₁Be the angle of main inclined surface with respect to flat surfaces, and θ ₂Be the angle of secondary inclined surface with respect to axis.

4. display device comprises:

At least one picture regulator;

Reception is used to form upright real image from the imaging device of the light of described at least one picture regulator;

A Fenier lens, it comprises a body, this body has a flat surfaces and the surface with structure that has periodic ridge, and this Fenier lens suitably is provided with so that incide on the surface with structure of Fenier lens from the light of imaging device;

A screen, its process imaging device and Fenier lens receive the light from described at least one picture regulator; And

Be in the scope between about 13 and 40 degree with respect to angle (AEP) wherein perpendicular to the line of this Fenier lens from the light of the outermost portion outgoing of Fenier lens.

5. according to the display device of claim 4, wherein each ridge comprises a smooth top and at least one inclined surface, top that this is smooth and flat surfaces extend substantially abreast, and this at least one inclined surface extends from this smooth top towards this flat surfaces, and the smooth top of each ridge is provided with a light shield layer.

6. according to the display device of claim 5, the width that wherein smooth top has changes according to the position of ridge.

7. according to the display device of claim 6, wherein this at least one inclined surface comprises a main inclined surface and a secondary inclined surface, this main inclined surface is set at a side on smooth top and is suitably designed so that light mainly incides on the body from main inclined surface, and should the pair inclined surface be set on the opposing opposite side of smooth top and main inclined surface.

8. according to the display device of claim 7, the width on wherein smooth top is determined by following formula: $d=p\frac{\tan r}{\tan (90-\mathrm{\&theta;}1)+\tan r}\&times;\&lsqb;1-\frac{\tan \mathrm{\&theta;}2}{\tan r}\&rsqb;---\left(1\right)$ Wherein d is the width on smooth top, and p is the spacing of ridge, and r incides chief ray on the body with respect to the angle of axis, θ from main inclined surface ₁Be the angle of main inclined surface with respect to flat surfaces, and θ ₂Be the angle of secondary inclined surface with respect to axis.

9. according to the display device of claim 4, wherein said at least one picture regulator comprises a plurality of LCD panel, and is provided with imaging device and Fenier lens for each LCD panel.

10. according to the display device of claim 9, wherein be provided with four groups of LCD panel, imaging device and Fenier lens, and each group is set at each four/part of rectangular area, and total viewing area of this screen is bigger four times from the visual required viewing area of a group of LCD panel, imaging device and Fenier lens than receiving.

11. according to the display device of claim 10, wherein between two groups of adjacent LCD panel, imaging device and Fenier lens, be provided with a dividing plate near the screen, be used for preventing that light from scattering to adjacent group from one group.

12. display device according to claim 4, wherein screen has predetermined viewing area, and described at least one picture regulator has the main viewing area and the peripheral compensatory zone of suitable setting, so that main viewing area forms image through imaging lens and Fenier lens on predetermined viewing area, and make peripheral compensatory zone just outside predetermined viewing area, form an image through imaging lens and Fenier lens.

13. display device according to claim 12, the described peripheral compensatory zone of wherein said at least one picture regulator is controlled, so that an image to be provided, this image is identical substantially with the part of the image that main viewing area near at least one picture regulator the peripheral compensatory zone provides.

14. according to the display device of claim 12, wherein said at least one picture regulator comprises a plurality of LCD panel, and is provided with imaging lens and Fenier lens for each LCD panel.

15. display device according to claim 14, wherein be provided with four groups of LCD panel, imaging device and Fenier lens, and each group is set in each four/part of rectangular area, and total viewing area of this screen is bigger four times than receive the required viewing area of image from one group of LCD panel, imaging device and Fenier lens.

16. according to the display device of claim 15, wherein between two groups of adjacent LCD panel, imaging device and Fenier lens, be provided with a dividing plate near the screen, be used for preventing that light from scattering to adjacent group from one group.

17. display device according to claim 14, wherein between two adjacent lcd display boards, the described peripheral compensatory zone of a LCD panel is controlled, so that an image to be provided, this image is identical substantially with the part of the image that main viewing area near the adjacent lcd display board the peripheral compensatory zone of a described LCD panel provides.

18. a display device comprises:

At least one picture regulator;

Imaging device receives the light from described at least one visual modulator, is used to form upright real image;

A Fenier lens, comprise a body, this body has a flat surfaces and the surface with structure that has periodic ridge, wherein each ridge comprises a smooth top and at least one inclined surface, the top that this is smooth and this flat surfaces extend substantially abreast, and extend on the top of this inclined surface from this smooth top towards each ridge, and Fenier lens is set, light is incided from imaging device on the body structure surface of Fenier lens, and the width on wherein smooth top changes according to the position of ridge; And

Screen is used for the light of process imaging device and Fenier lens reception from described at least one picture regulator.

19. display device according to claim 18, wherein at least one inclined surface comprises main inclined surface and secondary inclined surface, main inclined surface is arranged on the side on smooth top and is designed so that the light of autonomous inclined surface mainly to be incident on the body, and secondary inclined surface is arranged on the opposing opposite side of smooth top and main inclined surface.

20. according to the display device of claim 18, the width on wherein smooth top is determined by following relation: $d=p\frac{\tan r}{\tan (90-\mathrm{\&theta;}1)+\tan r}\&times;\&lsqb;1-\frac{\tan \mathrm{\&theta;}2}{\tan r}\&rsqb;---\left(1\right)$

Wherein d is the width on smooth top, and p is the spacing of ridge, and r incides chief ray on the body with respect to the angle of axis, θ from main inclined surface ₁Be the angle of main inclined surface with respect to flat surfaces, and θ ₂Be the angle of secondary inclined surface with respect to axis.

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