摘要:
[PROBLEMS] A method of producing a precision, low-cost resin molded article capable of improving a light utilizing efficiency and reducing a stray light caused by a light that enters a rise surface and is reflected off a reflection surface in an abnormal direction or refracted. [MEANS OF SOLVING PROBLEMS] A Fresnel lens sheet which comprises a prism row that is provided on the incident-side surface of the Fresnel lens sheet to deflect an incident light toward an exit side, at least part of the prism row having an incident surface for refracting an incident light from a light source, a reflection surface for totally reflecting light beam refracted at the incident surface, and a rise surface between the center-side terminal point of the incident surface and the outer periphery-side terminal point of the reflection surface, the three surfaces, that is the reflection surface, the incident surface and the rise surface constituting one unit of prism, characterized in that the rise surface is reversely tilted toward the outer periphery side starting at the crossing point between the incident surface and the rise surface, and a Fresnel light axis center portion is formed eccentrically so as to fall outside a lens sheet range.
摘要:
There are provided a rear projection screen and a rear projection display apparatus capable of achieving a large lenticular pitch Lp and a high pitch ratio Gp/Lp and suppressing moire. The rear projection screen includes a plurality of pixels with an outer edge having a rhombus shape inclined with respect to a horizontal direction and a vertical direction of a screen of the rear projection screen, and a lenticular lens sheet diffusing light emitted from a rear projection projector within a certain angle range. The plurality of pixels are arranged in such a way that their outer edges are adjacent to each other, a lens pitch Lp (mm) of the lenticular lens sheet satisfies Lp≧0.15, and a pitch ratio Gp/Lp of a pitch Gp (mm) of the pixels and the lens pitch Lp satisfies Gp/Lp≧1.0.
摘要:
A rear projection screen for use in a rear projection display apparatus contains a Fresnel lens sheet, a horizontal lenticular lens sheet capable of horizontally refracting the incident light, and a vertical lenticular lens sheet capable of vertically refracting the incident light, in this order from the incident side of the incident light, in which the lens center of the Fresnel lens sheet is arranged upward with respect to the mechanical center of the screen, and, in relation to this arrangement, black stripes of the vertical lenticular lens sheet are shifted with respect to the vertical lenticular lens.
摘要:
In a rear-projection screen comprising a Fresnel lens and a light-diffusing member such as a lenticular lens sheet, a rise angle in a central region of the Fresnel lens is smaller than a rise angle in an intermediate region thereof (e.g., the former is not larger than 3.degree. and the latter is larger than 3.degree. ). The rise angles may preferably gradually increase from the central region of the Fresnel lens toward the intermediate region thereof. The central region of the Fresnel lens may preferably be a region extending within the range of from 1/4 to 1/3 from the middle point of a diagonal of the rear-projection screen. Such a Fresnel lens is effective for improving white uniformity in the intermediate region of the rear-projection screen and eliminating color corn in the central region thereof.
摘要:
Novel 2-oxopyrrolidine compounds represented by the formula ##STR1## wherein R.sup.1 and R.sup.2 are hydrogen or alkyl group, respectively, A is alkylene group or phenyl substituted alkylene group, and B is alkylene group,or a salt thereof, a process for the preparation thereof, and a pharmaceutical agent comprising the compound or salt as an effective component.
摘要:
A liquid crystal display device has a liquid crystal cell, a liquid crystalline substance layer, a pair of polarizers, and an optical compensation element. The twist angle of the liquid crystal cell is set to 180 to 270 degrees. The optical compensation element has a twisted structure twisted in the opposite direction to that of the liquid crystal cell. The difference in the absolute values of the twist angles between the liquid crystal cell and the optical compensation element is from 40 to 100 degrees. The difference in retardation at a wavelength λ=550 nm between the liquid crystal cell and the optical compensation element is from 100 to 250 nm. When the absolute values of the differences in retardation at wavelengths λ of 400 nm and 550 nm between the liquid crystal cell and the optical compensation element are represented by ΔR(400) and ΔR(550), respectively, and the ratio D therebetween is represented by D=ΔR(400)/ΔR(550), D is within the range of 0.5 to 1.0.
摘要:
A complex diffraction device, which is excellent in designability, easy in setting the diffraction angle, adaptable to size increase, and easy to handle by adding a diffraction function resulting from an uneven pattern to the diffraction device comprising a liquid crystalline layer where the helical orientation of the smectic liquid crystal phase having a helical structure is maintained.
摘要:
According to the present invention, damage to a photo-detector disposed in clock signal extractor by means of an optical pulse having an optical power exceeding a rated value is prevented. A ring resonator generates a repetitive, high-frequency optical pulse. Optical branching circuit branches a portion of the optical pulse circulating through ring resonator, while optical branching circuit further branches a portion thereof to protective device. Pumping source generates an excitation light for exciting a rare-earth doped optical fiber. Optical multiplexer couples the optical pulse branched by optical branching circuit, and the excitation light. Upon excitation by means of the excitation light, rare-earth doped optical fiber amplifies and emits the incoming optical pulse. The optical power of the excitation light is adjusted such that the output of rare-earth doped optical fiber reaches a saturation power. Optical switch blocks the incoming optical pulse during the time period when pumping source is not emitting an excitation light, and during a fixed time period following the emission of the excitation light. In this manner, the entry of an excessively large optical pulse exceeding the saturation power into photo-detector at the time of starting up the power source is prevented. Optical attenuator attenuates the optical power of the optical pulse emitted from optical switch to an optical power which the photo-detector is capable of photo-detecting. Photo-detector converts the optical pulse emitted from protective device into an electronic signal; narrow band filter extracts a clock signal from the output of photo-detector; and electric amplifier amplifies the output of narrow band filter, and outputs a clock signal. Phase shifter adjusts the phase of this clock signal; electric amplifier amplifies the output of phase shifter, and outputs a clock signal to optical modulator. Optical modulator modulates the intensity of the light circulating through the ring resonator based on the clock signal, and generates an optical pulse.
摘要:
A double-faced lenticular lens sheet including at least one incident side lens formed on a first face of the double-faced lenticular lens sheet; and at least one corresponding emergent side lens formed on a second opposite face of the double-faced lenticular lens sheet; wherein light rays incident on the at least one incident side lens parallel to an optical axis thereof pass through the lenticular lens sheet and emerge from the at least one emergent side lens; an angle of refraction .theta.1 is formed by a straight line parallel to an optical axis of the at last one incident side lens and a light ray refracted by an incident plane passing through the lenticular lens sheet; an angle of refraction .theta.2 is formed by a straight line parallel to an optical axis of the at least one emergent side lens and the light ray refracted by and emitted from an emergent plane; .DELTA..theta.1 is an absolute value of the angle of refraction .theta.1 on the incident plane; .DELTA..theta.2 is an absolute value of an angle of refraction given by (.theta.2-.theta.1) on the emergent plane; a ratio between .DELTA..theta.1 and .DELTA..theta.2 given by (.DELTA..theta.2/.DELTA..theta.1) is 1.0 or more when a center of the lenticular lens sheet rests on the optical axis of the at least one incident side lens and a width of the lenticular lens sheet is 80% or less of the lens pitch of the at least one incident side lens.
摘要:
A rear projection screen is used for a projection optical system where projected lights perpendicularly enter the screen from the rear face of the screen includes a Fresnel lens sheet incorporating a prism and a lenticular lens sheet that horizontally disperses lights emitted from the Fresnel lens sheet incorporating a prism. The Fresnel lens sheet incorporating a prism has a linear prism, which acts as a linear Fresnel lens for converging image lights in the screen height direction, at the projection light source side, and has a circular Fresnel lens, which acts to converge image lights in the direction of the screen center, at the observer side. According to the rear projection screen, the peak screen gain is increased and the peripheral luminance ratio is improved without degrading light utilization efficiency.