The ultralow projection of eight groups of ten refraction-reflection types is than projection lens foundation structure
Technical field
The present invention relates to a kind of low projection than projection lens foundation structure, and a kind of more particularly to eight groups of ten refraction-reflection types surpass
Low projection is than projection lens foundation structure.
Background technology
Distance between projector and screen is directly proportional to picture dimension, and projector's off screen curtain is nearer, the picture chi projected
It is very little smaller, conversely, picture is then bigger.In limited space, with most short distance realize maximum sized curtain screen picture be work as
Where the demand that one is new in modern and following practical application, and the trend of projection field development.And short focus projection lens
Appearance makes everything become reality.Short focus projection lens possesses relatively low projection ratio, so-called projection than refer to projector distance with
The ratio between projection image width, identical projector distance, projection ratio is lower, and projected picture is bigger.Throwing equipped with short focus projection lens
Shadow machine needs only to tens centimetres of projector distance, can be achieved with larger projected picture.
The main flow of existing short focus projection lens is achieved in that refraction type and refraction-reflection type based on geometric optical theory.Wherein
The lens optical system of refraction type is all made up of refractor, and refractor includes spherical lens and non-spherical lens.It is catadioptric
The lens optical system of formula is made up of dioptric system and reflecting system, and dioptric system includes spherical lens and non-spherical lens, instead
The system of penetrating can be plane mirror, convex aspheric surface speculum, concave surface non-spherical reflector, convex free-form surface mirror or
Recessed free-form surface mirror.For projection ratio, the projection of refraction type short focus projection lens whole realization is than rank 0.6: 1
Level, this digitized representation be short focus projector short focus ability, ratio it is smaller explanation short focus ability it is stronger, for lower projection
Than the realization of rank, then refraction-reflection type short focus projection lens is needed to complete, therefore also known as ultrashort out-of-focus projection's camera lens.In many reality
In engineering projection, short focus projection lens needs have larger off-axis excursion capability, to meet to project off axis, therefore short focus projection lens
The design of head needs to consider situation about projecting off axis, and refraction-reflection type projection lens then needs have bigger off-axis offset, comes
Realize lower projection ratio.
Refraction-reflection type short focus projection lens can be divided into level crossing refraction-reflection type, aspherical mirror according to the type of internal system speculum
Three kinds of refraction-reflection type and free form surface mirror refraction-reflection type.For level crossing refraction-reflection type short focus projection lens, to reach smaller projection ratio, then
The volume of system can be bigger, and complex degree of structure can be higher, is unfavorable for the realization of product;And aspherical refraction-reflection type and free form surface
Refraction-reflection type, because the reflecting surface of speculum has its special curvature characteristic, so being advantageous to the aberration correction of system, volume
Miniaturization and the simplification of structure, it is the current ultrashort most common combination in out-of-focus projection field.It is however, existing aspherical
Refraction-reflection type and free form surface refraction-reflection type short focus projection lens optics foundation structure are still complex, including the refraction of 11-14 pieces is saturating
Mirror, aspherical containing 3-5, shank length, production technology is poor, and cost is high, and manufacturing technique requirent is high, and yield rate is low, these
Deficiency has had a strong impact on the development of ultrashort out-of-focus projection's technology, is the key technology difficulty that the field needs to solve.
The content of the invention
In view of above-mentioned condition, tied the invention provides a kind of ultralow projection of eight groups of ten refraction-reflection types than projection lens basis
Structure, its lens optical system is combined by reflecting system and dioptric system, possess the projection ratio less than 0.27: 1, it is whole in guarantee
On the premise of body image difference is excellent, lens construction realizes to be simplified to greatest extent, is shortened shank length, is improved production technology
Property and projected picture brightness, reduce production cost.
The present invention technical solution be:A kind of eight groups of ten refraction-reflection types are ultralow to be projected than projection lens foundation structure,
An object point on digital projector chip in screen is a picture point by the lens imaging, including from the side of the picture point to should
The reflecting system and dioptric system that the side of object point is set gradually;Wherein:
Reflecting system, including a convex surface even aspheric surface speculum, reflecting surface is in screen side;With
Dioptric system, including seven groups of nine refractors, and an aperture diaphragm, described nine refractors are from the picture
Point side to the side of the object point set gradually the first lens, the second lens, the 3rd lens, the 4th lens, the 5th lens,
6th lens, the 7th lens, the 8th lens, the 9th lens, wherein the 3rd lens and the 4th lens, the 7th lens and the 8th lens
Respectively double glued microscope groups, first lens, the second lens are negative curved month type, and convex surface is facing forward, and the 3rd lens are negative
Curved month type, and convex surface is facing forward, the 4th lens are biconvex, and curvature absolute value is big forward-facing, and the 5th lens are positive curved month type, recessed
Forward-facing, the 6th lens are positive curved month type, and concave surface is facing forward, and the 7th lens are biconvex, and curvature absolute value is small forward-facing, the 8th
Lens are negative curved month type, and concave surface is facing forward, and the 9th lens are biconvex, and curvature absolute value is big forward-facing, and the aperture diaphragm is set
The position between the 4th lens and the 5th lens is put, the reflecting system has identical primary optical axis with dioptric system, reflects
System is used to be reflected through the light beam that dioptric system is emitted;
The first lens in described dioptric system are spherical lens, and the convex surface face types of the second lens is sphere, concave surface face
Type is even aspheric surface, the 3rd lens, the 4th lens, the 5th lens, the 6th lens, the 7th lens, the 8th lens, the 9th lens
It is spherical lens;
The ratio between the equivalent focal length absolute value of described reflecting system and the equivalent focal length absolute value of dioptric system be 9.5~
13.0, the wherein equivalent focal length of reflecting system is negative value, the equivalent focal length of dioptric system be on the occasion of;
The ratio between described reflecting system and the spacing of dioptric system and the overall length of dioptric system are 0.39~0.51;
Described refraction-reflection type projection lens it is anti-more than for 4.5~6.5;
Described refraction-reflection type projection lens is applicable coloured light wave-length coverage:430nm~650nm.
In the present invention, first lens are using weight crown system optical glass material;Second lens use optical plastic
Or crown system optical glass material;3rd lens, the 4th lens, the 5th lens, the 6th lens, the 7th lens, the 8th lens,
9th lens are successively using lanthanum flint system, flint system, barium crown system, fluorine crown system, fluorine crown system, dense flint system, fluorine crown system optical glass
Material.
In the present invention, involved refraction-reflection type projection lens foundation structure carries out focal length scaling in proportion, and suitably adjusts
The matching relationship of each dominant aberration, the target surface size that can meet 1LCD, 3LCD, 1DMD type of skill are 0.55~0.7 inch of model
The use of the digital projector enclosed.
In the present invention, any or several index plane in lens construction can be changed to it is aspherical, can be to whole optics
The aberration correction of system.
Of the invention signified is anti-more than the absolute value for referring to the ratio between lens optical rear cut-off distance L ' and focal length f '.
Beneficial effect is possessed by the present invention:The projection lens gone out with this foundation structure form design, by with negative
The reflecting system of focal length and the dioptric system of positive focal length are formed, and reflecting system is a convex surface even aspheric surface speculum, refraction system
The spherical lens of the even aspheric surface lens and eight optical glass materials united only containing a piece of optical plastic material, it is simple in construction,
It is small, production technology and projected picture brightness are improved, greatly reduces production cost and resetting difficulty, and have and be less than
0.27: 1 ultralow projection ratio.Object plane is imaged on the reflecting surface of speculum first after dioptric system, then anti-by reflecting surface
It is incident upon in screen, the picture of high-quality sufficiently large smaller TV distortion can be projected in very short projector distance, is greatly reduced
Projector space.In addition, optical plastic can be used to adopt by the optical material of the non-spherical lens in dioptric system
With crown system optical glass, in the case of using crown system optical glass, it is processed, is fitted to aspherical with CNC Lapping & Polishing method
In the production and processing of smallest number, in the case of using optical plastic, it is processed with injection molding method to aspherical, suitable for big
The production and processing of batch, further promote the fast development of the ultrashort out-of-focus projection's technology of numeral.
Brief description of the drawings
Fig. 1 is the structural representation of the present invention;
Fig. 2 is Fig. 1 ray tracing schematic diagram.
Embodiment
Below in conjunction with accompanying drawing embodiment, the present invention is described in further detail, is only used for explaining the reality of the present invention
Example and possessed beneficial effect are applied, is not intended to limit protection scope of the present invention.
The ultralow projection of eight groups of ten refraction-reflection types as shown in Figure 1 is than projection lens foundation structure, on digital projector chip C
An object point by the lens imaging on screen A be a picture point, including the side from the side of the picture point to the object point is successively
The reflecting system 11 and dioptric system 12 of setting.Heretofore described reflecting system 11, including the reflection of convex surface even aspheric surface
Mirror 1101, its reflecting surface play the increase angle of visual field, balance aberration, correcting distorted effect in screen A sides.Described refraction
System 12, including reversely set gradually corresponding to screen A the first lens 1201, the second lens 1202, the 3rd lens 1203-1,
4th lens 1203-2, aperture diaphragm 1204, the 5th lens 1205, the 6th lens 1206, the 7th lens 1207-1, the 8th lens
1207-2, the 9th lens 1208.Wherein the 3rd lens 1203-1 and the 4th lens 1203-2 forms a double glued microscope group, rises and divides
Optical power, correcting chromatic aberration, the effect for reducing senior aberration amount, the 7th lens 1207-1 and the 8th lens 1207-2 form one
Double glued microscope groups, play correcting chromatic aberration, increase back work distance from the first lens 1201 are negative curved month type, and convex surface is facing forward
(setting camera lens when projecting working condition, before the end of speculum 1101 is, screen A ends are rear), play the increase angle of visual field, reduce eyeglass
Bore, the effect for widening rear focus intercept, the second lens 1202 are negative curved month type, and convex surface is facing forward, and concave surface face type is that even is non-
Sphere, play a part of increasing the angle of visual field, improve relative aperture, balance off-axis aberration, simplify structure, the 3rd lens 1203-1 is
Negative curved month type, and convex surface is facing forward, the 4th lens 1203-2 is biconvex, and curvature absolute value is big forward-facing, the 5th lens 1205,
6th lens 1206 are positive curved month type, and concave surface is facing forward, play improve big visual field, miniaturization and as it is of fine quality it is good between
Contradiction, the 7th lens 1207-1 are biconvex, and curvature absolute value is small forward-facing, and the 8th lens 1207-2 is negative curved month type, recessed
Forward-facing, the 9th lens 1208 are biconvex, and curvature absolute value is big forward-facing.It is saturating that the aperture diaphragm 1204 is arranged on the 4th
Between mirror 1203-2 and the 5th lens 1205.The 6th lens 1206, the 7th lens 1207-1 and the 9th lens in the present embodiment
1208 use fluorine crown system optical glass material, play a part of to widen back work distance from.In above-mentioned, described reflecting system 11
Equivalent focal length is negative value, and the equivalent focal length of dioptric system 12 is on the occasion of the ratio between both absolute values are 9.5~13.0.Described
The ratio between overall length of spacing and dioptric system 12 of reflecting system 11 and dioptric system 12 is 0.39~0.51.Described reflecting system
11 have identical primary optical axis 10 with dioptric system 12, and reflecting system 11 is used to be reflected through the light that dioptric system 12 is emitted
Beam.In embodiments of the invention, the optical performance parameter of the camera lens is:Focal length f '=- 4.7mm, relative aperture D/f '=1/
2.2, projection is than being 0.265: 1, and instead more than for 6.4, optical system overall length is 151mm, and wherein D is Entry pupil diameters.The present invention's
In embodiment, in the present invention, involved refraction-reflection type projection lens foundation structure carries out focal length scaling in proportion, and suitably adjusts
The matching relationship of each dominant aberration, the target surface size that can meet 1LCD, 3LCD, 1DMD type of skill are 0.55~0.7 inch of model
The use of the digital projector enclosed.In the present invention, the first lens in described dioptric system are spherical lens, the second lens
Convex surface face type is sphere, and concave surface face type is even aspheric surface, the 3rd lens, the 4th lens, the 5th lens, the 6th lens, the 7th
Lens, the 8th lens, the 9th lens are spherical lens.In the present invention, first lens are using weight crown system optical glass material
Matter;Second lens use optical plastic or crown system optical glass material;3rd lens, the 4th lens, the 5th lens,
6th lens, the 7th lens, the 8th lens, the 9th lens are successively using lanthanum flint system, flint system, barium crown system, fluorine crown system, fluorine crown
System, dense flint system, fluorine crown system optical glass material.In the present invention, involved refraction-reflection type projection lens it is anti-more than for 4.5~
6.5。
It is of the present invention instead more than the absolute value for referring to the ratio between lens optical rear cut-off distance L ' and focal length f '.
In the present invention, any or several index plane in lens construction can be changed to aspherical, so, pass through complexity
The design of change, sacrifice the aberration correction that processing technology is advantageous to whole optical system.
The camera lens of the present invention is a kind of digital projection camera lens for reflecting and reflecting the ultralow projection ratio combined, and it requires very little
Projection image TV distortion, and require very big picture and measure off axis, at the same require whole system appearance and size rationalize,
Miniaturization, its design optimization strategy are different from traditional total refraction numeral short focus projection lens.First, will according to design input
To ask, the picture for calculating camera lens is measured off axis, extrapolates the design image height of camera lens, then by projecting the focal length than extrapolating camera lens, so
Afterwards according to the image height and focal length of camera lens, suitable optical system model is established, i.e., first establishes a total refraction short-focus lens structure,
The focal length of reflecting system is extrapolated by the focal length of the total refraction camera lens again.Finally, according to light path can antidromicity principle, lens optical
Structure is designed by reverse optical path, sets the basic optical parameter of whole optical system in software:Image height, relative aperture, work
Wavelength, object distance range, while certain thickness (thickness foundation numeral throwing is inserted between lens imaging image planes and camera lens dioptric system
Shadow machine target surface size it is different and different) equivalent parallel glass plate, for the inside colour splitting prism of simulation numeral projector,
The camera lens so designed can just balance various aberrations caused by colour splitting prism inside digital projector well in projection.
On the basis of this, the Optimization Design that is combined using artificial and design software is transformed the optical system, optimized, directly
There is good aberration quality, uniform illuminance of image plane and good manufacturability to the camera lens.In optimization process pay attention to
Shi Gengxin and the various optimization target values of adjustment.
In order to illustrate embodiments of the invention, when camera lens equivalent focal length is 1, its Optic structure parameter is as follows:
S1 even aspheric surface parameters:
Conic constant (K) |
-20.32 |
4 level numbers (A) |
1.95e-006 |
6 level numbers (B) |
-2.21e-009 |
8 level numbers (C) |
1.47e-012 |
10 level numbers (D) |
-4.90e-016 |
12 level numbers (E) |
5.88e-020 |
S5 even aspheric surface parameters:
Conic constant (K) |
-0.55 |
4 level numbers (A) |
0.013 |
6 level numbers (B) |
-4.16e-003 |
8 level numbers (C) |
7.63e-004 |
10 level numbers (D) |
-6.67e-005 |
12 level numbers (E) |
2.36e-006 |
It is 430nm~650nm that the lens optical structure of the embodiment of the present invention, which is applicable color wave-length coverage,.
Fig. 2 gives the ray tracing schematic diagram of the embodiment of the present invention.As can be seen from the figure lens construction is each specific regards
The feature light a trends of field, and incoming positions of the feature light a in each refractive lens surface and the reflection in mirror surface
Position.