using excimer laser ablation was also repo rted to fabricate direct methods are usually limited to low v olume production have to be used. For example, optical grade polymers can be injection mol ded into extremely complex but accurate geometries. These optics, however, do not perform well under that are required for many precision applications. The biggest problem with polymer devices is the issue of thermal stability . Optical polymer devices may work well at room temperature, but the geometry and optical properties of these polymer devices will deteriorate at higher temperature. Except for some special materials such as fluoropolymers, the service temperature of most optical polymer materials is lower water, resulting in a change of geometry as the moisture of the environment va ries. On the other hand, optical glasses have been and will continue to be the mate rials of choice for high precision imag ing optics mainly becaus e the service temperature of typical optical glass materia ls is high, usually from 400 to 700 C. In addition, the thermal expansion of glass materials is in general one order of magnitude less than most using grinding and polishing is time-consuming and costly . glass DOEs, can be a very attractive approach [ and micro-scale optical feat ures can be fabricated by preci sion Yi used fused silica as a mold, which was fabrica ted by accuracy of the mold and compared optical performance between the mold and the molded lenses. Tanaka the chromatic aberration of the objective lens for D VD (digital applied to the mold insert before diamond turning. In a departure from the previous attempts, the primary goal of this research is to develop an economical proc ess for low cost, high quality conv entional size glass DOEs that are suitable for industrial production. The aim of this paper is and mold materials and pro cess parameters will b e evaluated in lower cost and high quality products. The proposed process For a single lens, spherical aberration can be eliminat ed by the use of aspherical design. However , because of dispersion of some glass material s, ch romatic aberration of a single lens could not be reduced by geometry manipulation alone. approach to compensating for chromatic aberration is to form an achromat, i.e. a doublet. In a doublet design, one of the lenses is convex made from a cro wn glass with positive dispersion while the other lens is concav e made from a flint glass with negative dispe rsion. Two lenses with opposite dispersion power are mounted together so the overall chroma tic aberration of the compound lens is lower than a singlet. Inadvertently , the introduction of an extra lens increases the size as well as the complexity of the optical system. It also raises the issues of alignment during assembly. On the other hand, diffractive optical elements have negati ve dispersion [ 18 ]; therefore instead of using another lens, these optical components with micro/nano fe atures can be applied to a lens surface to form a singlet and compensate for the In this paper, a hybrid aspherical diffracti ve glass lens is aberration was compensated by t he aspherical design. The specifications of this hybrid lens, which represent a typical objective lens in a comp act optical syst em, are listed in table P-SK57 is a Schott glass that is designed specifically for precision glass molding. The wavelength was chosen to allow the lens to work in the visible light range. Specifically , the D line ( 587 5618 nm) was set as the main working wavelength. DOEs on an aspherical surface highlight the singlet design. Figure shows the layout of the hybrid was used in the optical design. A planar -convex le ns was designed to reduce the cost of mold fabrication. DOEs could be designed on either p lanar surface (first surface) or aspherical surface (second surface). Obviously, DOEs on the aspherical surface was beneficial for the sine condition [ which reduced the spherical and coma aberration. It was also a preferred design for m old fabrication since it el iminated the need for alignment of the cutting tool because there was only one surface needed to be diamond-turned. The need for alignment during compression molding was also subsequently In this case, the first surface, S1 in figure surface. The second surface, S2, is the aspherical diffractive surface, which is modeled using Bin ary 2 element in ZEMAX. Binary 2 elements describe an even aspherical surface with diffraction power. The asph erical surface can be expressed by
1. How can I get rid of the awful smell inside of my plastic protein shaker cup?
bleach will probably work - but seriously, do you want to drink out of a plastic cup that absorbs odors and hangs on to them that long? can not be too healthy....can you switch to glass or stainless steel?
2. Glass Pipe or Glass Water Pipe?
Smoking is a habit that is popular among many people. It is true that once you are in to smoking it may be very difficult to resist the habit. There are number of health hazards that can affect your body due to the smoking habits. This awareness is spread to people through many ways in order to bring a tobacco free world. People are slowly turning to be conscious about their health and they are turning to quite smoking through the traditional means which causes inhalation of hot smoke
3. How should I repair a color print that ended up in the garbage by accident?
OK, here's what I did.Put it in the scanner and flattened it with some heavy books. This cracked the emulsion in several places, but at least I had a backup image to work with.Wet the photo with distilled water and flattened it. This fixed the emulsion cracks. I let the photo dry before scanning it again, but unfortunately it curled up again.Wet the photo again, dried it off as well as I could, and scanned it. This did not work too well; the damper areas on the photos were quite visible as darker splotches on the image. However, the cracks were still gone. Wet the photo one more time, placed it between 2 sheets of waxed paper, piled up some heavy books. I am going to let that sit for a few days to dry out then will scan it. Doing this will fix the emulsion cracks and hopefully it will be dry enough there wo not be any water splotches. Hopefully the wax on the paper will prevent the photo from sticking to the paper.The waxed paper was a bad idea. The wax is not quite flat on the waxed paper, so all of the waxy bumps got transferred to the emulsion and resulted in a visible noisy pattern of creases and bubbles on the photo.I attempted several approaches to remove this noisy pattern. What finally worked was to soak the photo thoroughly (15 minutes in distilled water), then lay the photo emulsion side down on a very clean sheet of glass. I then used a tungsten roller I just happened to have to roll the back of the photo flat and press the photo hard against the glass. That smoothed out the emulsion very well, and also flattened the photograph. I then used a hot air dryer to dry out the photo quickly (not giving it time to warp if I hung it in the air.)