Abstract: An optical system that relays light to a machining lens to be used for machining on a workpiece includes a spatial light modulator and a second lens arranged between the spatial light modulator and the machining lens, a distance D from the second lens to a machining lens pupil is D = f2 - Mf2, and a distance D1 from the spatial light modulator to the second lens is D1 = f2 - f2/M, and the spatial light modulator has a conjugate relation with the machining lens pupil of the machining lens, where f2 is a focal length of the second lens, and M is a projection magnification from the spatial light modulator to the machining lens pupil of the machining lens.

Abstract: A laser processing apparatus includes: a light flux separating-and-combining device configured to polarize and separate a laser light into two polarized light fluxes having polarization orthogonal to each other and emit the two light fluxes with their optical paths matching each other toward different regions of a spatial light modulator, and configured to combine the two polarized light fluxes modulated by the spatial light modulator and emit the two light fluxes toward a condenser lens; and a controller configured to control hologram patterns presented by the spatial light modulator for respective regions of the spatial light modulator irradiated with the two polarized light fluxes such that the laser light is condensed by the condenser lens at two positions different from each other in a thickness direction inside of the wafer and the same as each other in a relative movement direction of the laser light to form modified regions.

Abstract: A laser processing apparatus includes: a light flux separating-and-combining device configured to polarize and separate a laser light into two polarized light fluxes having polarization orthogonal to each other and emit the two light fluxes with their optical paths matching each other toward different regions of a spatial light modulator, and configured to combine the two polarized light fluxes modulated by the spatial light modulator and emit the two light fluxes toward a condenser lens; and a controller configured to control hologram patterns presented by the spatial light modulator for respective regions of the spatial light modulator irradiated with the two polarized light fluxes such that the laser light is condensed by the condenser lens at two positions different from each other in a thickness direction inside of the wafer and the same as each other in a relative movement direction of the laser light to form modified regions.

Abstract: A height position of a surface of a wafer can be detected accurately and stably without being affected by variation in a thin film formed on the surface of the wafer. An AF (autofocus) device irradiates the surface of the wafer W with an AF laser beam, detects reflection light thereof for each wavelength with a detection optical system. An AF signal processing unit outputs a displacement signal indicating displacement of the surface of the wafer to a control unit on the basis of a detection result of the detection optical system. Moreover, the AF device includes a focus optical system disposed in an irradiation optical path which is an optical path from the light source unit to a light converging lens. The focus optical system adjusts a light converging point of the AF laser beam in a wafer thickness direction.

Abstract: A height position of a surface of a wafer can be detected accurately and stably without being affected by variation in a thin film formed on the surface of the wafer. An AF (autofocus) device irradiates the surface of the wafer W with an AF laser beam, detects reflection light thereof for each wavelength with a detection optical system. An AF signal processing unit outputs a displacement signal indicating displacement of the surface of the wafer to a control unit on the basis of a detection result of the detection optical system. Moreover, the AF device includes a focus optical system disposed in an irradiation optical path which is an optical path from the light source unit to a light converging lens. The focus optical system adjusts a light converging point of the AF laser beam in a wafer thickness direction.

Abstract: A laser dicing device includes a laser light source, an AF light source, a light path of the processing laser light and a light path of the AF laser light being partially shared with each other, a condenser lens arranged on the shared light path between the first laser light and the second laser light, an AF signal processing unit that generates a focus error signal based on reflected light of the AF laser light reflected by the surface of the wafer, a controller that moves the condenser lens such that a distance between the condenser lens and the surface of the wafer is made constant based on the focus error signal, and a focus lens group that adjusts the position of the condensing point of the AF laser light in a state where the position of the condensing point of the processing laser light is fixed.

Abstract: A laser dicing device includes a laser light source, an AF light source, a light path of the processing laser light and a light path of the AF laser light being partially shared with each other, a condenser lens arranged on the shared light path between the first laser light and the second laser light, an AF signal processing unit that generates a focus error signal based on reflected light of the AF laser light reflected by the surface of the wafer, a controller that moves the condenser lens such that a distance between the condenser lens and the surface of the wafer is made constant based on the focus error signal, and a focus lens group that adjusts the position of the condensing point of the AF laser light in a state where the position of the condensing point of the processing laser light is fixed.

Abstract: The optical film thickness measuring device comprises a spectral reflectance measuring device for measuring spectral reflectance of two layers of a two-layer optical film, a memory device for storing, as reflectance data theoretical values of optical thickness and refractive index of each layer of the two-layer optical film as well as those of reflectance of the two-layer optical film, a data selecting device for selectively reading out the reflectance data corresponding to the measuring wavelengths for measured values of spectral reflectance and a film thickness deciding means for determining thickness of each layer of the two-layer optical film on the basis of the selected reflectance data and the measured spectral reflectance. This optical film thickness measuring device is capable of quickly and accurately measuring thickness of each layer of two-layer optical films.

Abstract: The optical measuring device of film thickness consists of a spectral reflectance measuring device and a film thickness deciding device. The film thickness deciding device comprises a reflectance operating device, an evaluation function operating device, a global optimization device, a local optimization device, and settlement judging devices added to the global optimization device and the local optimization device respectively. A data selecting device may be interposed between the spectral reflectance measuring device and the film thickness deciding device. The optical measuring device of film thickness is capable of measuring thickness of individual layers of a multi-layer film simultaneously, speedily and accurately.

Abstract: In order to insure a high degree of precision of measurement with a simple structure, the apparatus for measuring reflectivity employs an objective lens, a half-mirror disposed rearwardly of the objective lens and a light source means disposed on one of the optical paths so split by the half-mirror for emitting an annular bundle of light. A fine aperture stop is disposed on the other optical path so split by the half-mirror. A light-responsive device is disposed rearwardly of the fine aperture stop, a memory is coupled to the light-responsive device and a mathematical operation device is connected to the memory. An indicating device is connected to the mathematical operation device. An annular bundle of light is collected onto an examination surface via the half-mirror and the objective lens, and that the reflection light produced at the examination surface is caused to impinge onto the light-responsive device via the objective lens, the half-mirror and the fine aperture stop.

Abstract: A behind-stop type photographic camera lens system designed for an aperture ratio of F/2.8, a field angle of 60.degree., a short total length less than 0.37 f and favorably corrected aberrations, and comprising a first positive meniscus lens component, a second positive meniscus lens component, a third negative lens component, a fourth cemented lens component consisting of a biconvex lens element and a negative lens element.

Abstract: A lens system for photographic cameras which has a very short total length and wherein aberrations are favorably corrected. Said lens system comprises a first positive meniscus lens component, a second biconcave lens component and a third cemented doublet component, and said lens system satisfying the conditions enumerated hereunder:(1) 0.23f<.SIGMA.d<0.3f(2) 0.55f<f.sub.1 <0.59f(3) -0.37f<f.sub.2 <-0.32f(4) n.sub.1 >1.71(5) n.sub.2 <1.67(6) .vertline.r.sub.7 .vertline.>4.8f(7) 0.26f <-r.sub.6 <0.34f(8) .vertline.r.sub.3 .vertline./r.sub.4 >6.0(9) .nu..sub.1 -.nu..sub.

Abstract: A retrofocus type wide-angle lens system comprising five components of five lens elements including a front diverging lens group consisting only of a single lens element and a thick positive lens element arranged at the second stage, said lens system being so designed as to have a short total length and favorably correct various aberrations.