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A new single digital stereo dual-channel projection system is introduced and a dual-channel projection lens is designed by using ZEMAX software and an artifical structure method.The structure of lens based on refraction type is off-axis and with three optic axes.It includes a former group and a back group.The former group is composed of seven glass sphere lenses and the back group consists of two identical and symmetrical structures composed of four glass sphere lenses.The lens has a total length of 243.8 mm,a maximum diameter of 93 mm,and a focal length of 20.23 mm.Moreover,its Field of View(FOV) and F-number are 36° and 2.01 respectively,and the distance of two assistant optic axes and the Back Focal Length(BFL) are 8.2 mm and 37.8 mm,respectively.The system performs excellently in image quality,and has advantages of small size,simple structure and low cost.

To match the projecting images on dome screens from different types and specs of mainstream digital engineering projectors,a basic design method for a general projection fisheye zoom lens was presented.First,based on the characteristics and universality of the projection fisheye lens,the optical structure used in the final system was defined.By configuring the initial parameters of moving unit bestly,the moving path of compensating group was linearized to construct synchronously two cam curves to be standard helical lines.Then,image surface position was kept steady during a zooming process by controlling the spherical aberration of front fixed group and the focal length of back fixed group.The final design indicates that the optical system can always keep a full field angle of view of 160° and a F# of 2.0 as it uses two moving components that contain a positive zooming group and a negative compensating group.By controlling parameters reasonably,the system can match prisms of different effective optical thicknesses from 16.5 mm to 26 mm in several kinds of digital projector engines,and also can match digital engineering projectors by using 1LCD,3LCD and 1DMD technologies with the chip sizes from 16-24 cm(0.63-0.95 in) and the length-width ratio of chip in 16∶9 and 4∶3 when the image shift is within ±0.03 mm.The design can fulfill the requirements of common and general projections with its simpler structure and good technology.

To satisfy the projection demand of cinemas with different size,based on mechanical compensation theory,a digital cinema projection lens is designed,and the cam curve is provided.The lens consists of four groups of nine glass lenses,and all the lens surface is spherical.Through comparing with the classical projection zoom lens,the character of the lens designed in the article is introduced clearly.Focal length is 26～28.3 mm,the relative aperture is 1/1.7,the total length is 158 mm,and the caliber is 71 mm.Distortion is less than 2%,at the frequency of 44.6 lp/mm,the axile MTF is higher than 0.68,the meridian MTF of the largest field is higher than 0.38,and the saggital MTF of the largest field is high than 0.58.The design results show that this lens has the merits of high brightness,steady image surface,compact structure and easy to process.

To fill the vacancy of domestic short focal range digital movie zoom projection lens and to meet the requirement of the market,a digital movie zoom projection lens for 0.65 inch DLP 1.3 K digital movie projector was designed by the mechanical compensation method.It includes the former fixed group,the zoom group,the compensation group and the last fixed group.It is composed of ten glass sphere lenses,and the zoom group is composed of one negative lens,the compensation group is composed of two doublet lenses.The total length of the digital movie zoom projection lens is 170 mm,the full aperture is 70 mm.Its focal length range is 14.5~18.2 mm,F-number is 2,projection ratio range is 0.99∶1~1.23∶1,and the BFL is 32.6 mm.The cam curves were designed with the method of equal interval zoom.The image quality in each focal length is excellent with advantages of simple structure,small size,and low cost,and its cam curves are smooth without cam inflexions and processed easily.

To meet the requirement of market,a short focal digital projection lens for 0.8 inch digital light processing(DLP) projectors is designed.The total length is 172.6 mm,and the full aperture is 70 mm.The lens uses a retrofocus structure,and it is composed of six glass lenses and one plastic lens(two even aspheric surfaces).Its FOV is 80°,F-number is 2.1,retrofocus proportion is 3.17∶1,and projection ratio is 0.76∶1.Its MTF in all field is less than 28° that is higher than 0.6 at the limiting spatial frequency of 37 lp/mm.The lateral color is less than 3.5 μm.The distortion of the full of view is less than 1.1%.Its image quality is excellent with advantages of simple structure,small size,easy process and low cost.

To realize the miniaturization and light weight of the digital projector,a wide-field angle mini lens for 0.55 inch DLP was designed.The total length is 69 mm,the full aperture is 25 mm,and it is composed of five glass lenses and two plastic lenses(4 aspheric surfaces).The lens used an inverted telephoto structure,with ZEMAX software as the optimize tool.Its F-number is F/2.4,the projection ratio is 0.73∶1,and it can project a 40 inch picture from 60 cm away.The distortion of the full field is less than 1%.Its image quality is excellent that the MTF of center field is 0.75,and the MTF of 1.0 field is 0.42,with advantages of small size,light weight,low cost,simple structure and easy process.