CN111679444A - Naked eye 3D grating capable of increasing light splitting angle - Google Patents

Abstract

The 3D grating disclosed by the invention is formed by compounding a layer of convex cylindrical mirror grating and a layer of concave cylindrical mirror grating, and the middle of the convex cylindrical mirror grating and the concave cylindrical mirror grating is kept at a proper distance, namely the convex cylindrical mirror grating and the concave cylindrical mirror grating are abbreviated as the convex cylindrical mirror grating. Through enlarging the beam splitting angle and shortening the viewing distance, the naked eye 3D display can be realized by handheld devices such as mobile phones and PADs through the outer film pasting technology, and meanwhile, the screen protection effect is achieved. The smart mobile phone is pasted with the 3D grating film, and 3D shooting and displaying can be realized by matching with a special APP, and meanwhile 2D displaying and touch functions are not affected.

Description

Naked eye 3D grating capable of increasing light splitting angle

The technical field is as follows:

the invention relates to a naked eye 3D grating capable of increasing a light splitting angle, wherein the naked eye 3D grating can be used for an external adhesive film of personal handheld equipment such as a smart phone and a PAD.

Background art:

the 3D grating is an important device for realizing naked eye 3D display, and the 3D grating mainly comprises a lenticular grating and a slit grating which are respectively obtained according to convex lens imaging and pinhole imaging principles and through one-dimensional simplification. One important characteristic of 3D gratings is: the light rays emitted from two adjacent pixels on the display plane go through the optical center of a cylindrical mirror unit or a slit and then exit straight, as shown in fig. 1. For the display screen on the handheld device, the viewing distance H is approximately equal to 350mm, the pupil distance L of human eyes is approximately equal to 65mm, and the point distance P of the 5.5-inch 1080P display screen is approximately equal to 0.063mm, so that the focal distance D of the 3D grating can be estimated to be approximately equal to 0.34 mm. Considering the distance from the pixel plane to the outer side of the display screen and the thickness of the 3D grating film, at such a short focal distance, the 3D grating can only be placed between the touch screen and the display screen, i.e. the inner film pasting mode.

By adopting naked eye 3D mobile phones and PADs with inner films, nearly 10 brands appear in the current market, and the 3D display effect meets the use requirement. However, the bigger market demand is that the development of outer pad pasting technique realizes bore hole 3D demonstration, and 3D grating film is pasted to arbitrary smart mobile phone promptly, can reach the purpose of protecting the screen, and the cooperation APP can also realize bore hole 3D demonstration, keeps 2D demonstration and touch function unaffected simultaneously. The 3D mobile phone shell adopting the outer pasting film display is limited by the technical characteristics of the 3D grating, and the nearest viewable distance is larger than 800mm and far larger than the normal handheld distance.

The invention content is as follows:

the invention discloses a naked eye 3D grating capable of increasing a light splitting angle, and aims to shorten the viewing distance of a grating film attached outside a screen to a normal handheld range by enlarging the light splitting angle, so that handheld equipment such as a mobile phone and a PAD can realize naked eye 3D display by attaching a grating protective film outside.

As shown in fig. 3, the naked-eye 3D grating capable of increasing the splitting angle is formed by combining a layer of convex lenticular grating and a layer of concave lenticular grating, and a suitable distance D is maintained between the convex lenticular grating and the concave lenticular grating. The concave lens virtual object imaging optical path diagram shown in fig. 2 explains the principle that the convex-concave lenticular grating can display naked-eye 3D. The distance between the image plane of the display screen and the convex cylindrical mirror grating is the object distance u₀Convex cylindrical mirror with focal length f₀，u₀＞f₀The pixel points on the image form an inverted real image through a corresponding cylindrical mirror, and the image distance is v₀. When the concave lens imaging optical path diagram is made, a virtual object and a real object are separated, the virtual object refers to an image formed by a previous optical device and meets a next optical device before reaching an imaging point, wherein the previous optical device refers to a convex cylindrical mirror, and the next optical device refers to a concave cylindrical mirror. Because the light emitted from the convex cylindrical mirror enters the concave cylindrical mirror before reaching the imaging point, i.e. v₀> d, so it is virtual imaging for a concave cylindrical mirror. When u is₁＝f₁When the virtual object is located on the focal plane of the concave cylindrical mirror, the imaging position is at infinity, namely, the light emitted from the concave cylindrical mirror is parallel light, and the direction deflects outwards, so that the beam splitting angle is increased.

For comparison, the image plane of the conventional lenticular grating is located on the focal plane, and the light rays emitted by the pixel points are converted into parallel light to be emitted out after being imaged by the lenticular lens，u₀＝f₀。

Obviously, the convex-concave cylindrical lens grating stereo imaging satisfies the following conditions:

u₀＞f₀

v₀＝d+f₁

when the film is used as an external film of a mobile phone, the object distance u₀The total thickness from the image plane of the display screen to the outer surface layer of the touch screen is less than or equal to 0.6mm, otherwise, the touch screen function is influenced.

The magnitude of the increase in the splitting angle can be derived from the lens imaging formula:

the greater the distance d between the convex and concave cylindrical lenses, the greater the focal length f of the concave cylindrical lens₁The smaller the size, the larger the increase of the splitting angle, but the size is limited by the total thickness of the convex-concave lenticular grating and the small focal length processing technology.

The design method of the convex-concave cylindrical lens grating parameters comprises the following steps:

a) determining the grid pitch p of the grating according to the pixel density of the display screen, wherein the p is 2-3 times the size of the pixel;

b) determining an object distance u based on a total thickness of a display screen pixel plane to an outer surface of a touch screen₀；

c) D and f are determined according to the beam splitting angle amplification requirement and the total thickness of the grating film₁Calculate v₀；

d) According to the lens imaging formula, from u₀、v₀Calculate f₀。

Description of the drawings:

fig. 1 is a schematic view of a lenticular grating beam splitter.

Fig. 2 is a concave lens virtual object imaging optical path diagram.

Fig. 3 is a schematic view of concave-convex lenticular grating spectroscopy.

Fig. 4 is a sectional view of the lenticular lens.

Fig. 5 is a cross-sectional view of a prism-free lenticular lens.

The reference numbers in the figures are as follows:

1 lenticular lens, 2 pixel planes, 3 pixel points, 4 emergent rays, 5 right eyes, 6 left eyes, 7 convex lenses, 8 convex lens focuses, 9 concave lenses, 10 concave lens focuses, 11 lens optical axes, 12 left eye pixels, 13 right eye pixels, 14 lens optical centers, 15 convex cylindrical lens gratings, 16 concave cylindrical lens gratings, 17 transparent substrates, 18 convex and concave cylindrical lens gratings, 19 convex cylindrical lens grating films, 20 concave cylindrical lens grating films, 21 transparent adhesive layers and 22 low-refractive-index adhesive filling layers.

The 3D grating disclosed by the invention can realize naked eye 3D display by a handheld device such as a mobile phone, a PAD (PAD application) and the like through an external film pasting technology by enlarging a beam splitting angle and shortening a viewing distance, and has a screen protection effect. Compared with a special naked eye 3D mobile phone with an internal grating film, the production cost and the market popularization difficulty are reduced.

The specific implementation mode is as follows:

the first embodiment is as follows: the structure of convex-concave cylindrical lens grating.

The grating pitch of the convex-concave cylindrical lens grating is determined according to the resolution of a mobile phone screen, the density range of pixels is generally 400-600 dpi, and the grating pitch can be designed to be 0.1-0.18 mm. The convex-concave cylindrical lens grating belongs to a composite grating, the distance d between the optical centers of two layers of gratings is about 0.5mm, the grating pitches of the gratings are slightly different, p₀/p₁1.0015. When the grating-type mobile phone external film is used as a mobile phone external film, the grating can be obliquely configured, the same grating can adapt to different mobile phone screens through the parameter setting of a mobile phone APP, and the grating-type mobile phone external film does not need to be strictly aligned when being attached to the mobile phone screens.

The required exit splitting angle β of the grating is 11 degrees, the thickness of the touch screen of the mobile phone is about 1mm, and the specific value u of the mobile phone can be tested₀The sampling width range of the 3D image pixels is 2-3 pixels, and can be a small value, and the appropriate sampling width and the grating inclination angle are set, so that the range of α is 4-5 degrees, and then D/f₁Has a range of 1 to 2, and a focal length f of the concave cylindrical mirror₁The value range of (A) is 0.25-0.5 mm. With f₁＝0.3mm，d＝0.5mm，u₀For example, 1.2mm, the focal length f of the convex cylindrical mirror can be calculated₀＝0.48mm。

Convex and concave cylindrical lens grating molds are respectively manufactured according to designed grating parameters, and after UV glue or transparent sheet base materials with required refractive indexes are selected, the convex and concave cylindrical lens gratings can be produced by adopting different processing technologies. As shown in fig. 4A, the upper and lower surfaces of a transparent film base (17) with a certain thickness are compounded with an upper convex lenticular grating (15) and a concave lenticular grating (16) by adopting a UV curing molding process; as shown in fig. 4B, a thermoplastic process is adopted to directly extrude and form a convex lenticular grating and a concave lenticular grating on the upper surface and the lower surface of the transparent film base to form an integrated convex-concave lenticular grating (18); as shown in fig. 4C, the convex lenticular film (19) and the concave lenticular film (20) which are respectively formed in advance are bonded together by a transparent adhesive layer (21).

In this example, the arc of the concave cylindrical mirror cross section is replaced by a polygon, so that the imaging effect of myopia can be achieved.

Example two: the structure of prism-free concave-convex lenticular grating.

When the convex-concave lenticular grating is used as a mobile phone film, the convex surface structure can affect the bonding and touch quality, as shown in fig. 5A, the convex surface of the convex-concave lenticular grating (18) is leveled by using a low-refractive-index glue filling layer (22), or as shown in fig. 5B, the upper surface and the lower surface of the convex-concave lenticular grating (18) are leveled by using the low-refractive-index glue filling layer (22), and a prism-free convex-concave lenticular grating is formed. The refractive index of the low-refractive-index glue is generally 1.3-1.4, the refractive index of the lenticular grating layer is generally 1.50-1.7, and the relative refractive index of the low-refractive-index glue and the lenticular grating layer is reduced, so that the curvature radius of the convex and concave lenticular lenses needs to be recalculated to keep the focal length to meet the design requirement.

If the liquid crystal with the refractive index capable of changing along with the driving voltage is adopted to replace the low-refractive-index glue layer, the purpose of 2D/3D grating switching can be achieved.

Claims (10)

1. The naked eye 3D grating capable of increasing the light splitting angle is characterized in that the light splitting angle of emergent light is enlarged through compounding of two layers of gratings, and the optimal viewing distance of a naked eye 3D image is shortened.

2. The 3D grating of claim 1, further characterized in that the 3D grating is comprised of a layer of convex lenticular grating and a layer of convex lenticular gratingThe concave cylindrical mirror grating is compounded, a proper distance d is kept between the concave cylindrical mirror grating and the convex cylindrical mirror grating, and the distance between the image plane and the convex cylindrical mirror grating is an object distance u₀Convex cylindrical mirror with focal length f₀，u₀＞f₀The pixels on the image form an inverted real image through a corresponding cylindrical mirror, and the image distance is v₀The light exiting from the convex cylindrical mirror enters the concave cylindrical mirror before reaching the imaging point, i.e. v₀D, for concave cylindrical mirror, is virtual imaging when u₁＝f₁When the virtual object is located on the focal plane of the concave cylindrical mirror, the imaging position is at infinity, namely, the light emitted from the concave cylindrical mirror is parallel light, and the direction deflects outwards, so that the beam splitting angle is increased. .

3. The 3D grating of claim 2, further characterized in that when used as a mobile phone film, D is 0.6mm or less, and the design sequence of the convex-concave lenticular grating parameters is:

a) determining the grid pitch p of the grating according to the pixel density of the display screen, wherein the p is 2-3 times the size of the pixel;

b) determining an object distance u based on a total thickness of a display screen pixel plane to an outer surface of a touch screen₀；

c) D and f are determined according to the beam splitting angle amplification requirement and the total thickness of the grating film₁Calculate v₀；

d) According to the lens imaging formula, from u₀、v₀Calculate f₀。

4. The 3D grating of claim 3, further characterized in that the density of pixels of the cell phone screen ranges from 400 to 600dpi, the grating pitch ranges from 0.1 to 0.18mm, the distance D between the optical centers of the two layers of gratings is about 0.5mm, and the grating pitch ratio p₀/p₁And the grating is obliquely configured, and the same grating can adapt to different mobile phone screens through the parameter setting of the mobile phone APP, and does not need to be strictly aligned when being attached to the mobile phone screen.

5. The 3D grating of claim 4, further characterized in that the split angle β of the grating exit is ≈ 11,the sampling width range of the 3D image pixels is 2-3 pixels, and can be a small value, and the suitable sampling width and the grating inclination angle are set, so that the range of α is 4-5 degrees, and D/f is₁Has a range of 1 to 2, and a focal length f of the concave cylindrical mirror₁The value range of (A) is 0.25-0.5 mm.

6. The 3D grating of claim 2 or 5, further characterized in that the upper and lower surfaces of the transparent substrate (17) of a certain thickness are combined with the upper convex lenticular grating (15) and the concave lenticular grating (16) by a UV curing molding process.

7. The 3D grating of claim 2 or 5, further characterized in that the convex lenticular grating and the concave lenticular grating are extruded directly on the upper and lower surfaces of the transparent substrate using a thermoplastic process to form an integrated convex-concave lenticular grating (18).

8. The 3D grating of claim 2 or 5, further characterized in that the pre-formed convex lenticular grating film (19) and concave lenticular grating film (20) are bonded together by a layer of transparent glue (21).

9. The 3D grating of claim 6 or 7, further characterized in that the convex surfaces of the lenticular grating (18) are leveled with a low refractive index paste fill layer (22), or the top and bottom surfaces of the lenticular grating (18) are leveled with a low refractive index paste fill layer (22) to form a land-free lenticular grating.

10. A 3D grating as claimed in claim 2 further characterized in that the arc of the cross section of the concave cylindrical mirror can be replaced by a polygonal line.

Images