Abstract: A data transmission system for transmitting an electrical data to a nerve cell. A data receiving system for receiving an electrical data from a nerve cell has at least two phototransistor crystals that is stimulated by light to form an electrical signal; an image source that allows the light to be sent to the phototransistor crystals and allows controlling the amount of light transmitted to each phototransistor crystal independently of each other, and at least one control unit that is connected to the image source that controls the amount of light transmitted from the image source to each of the phototransistor crystals.

Abstract: An optical cell for performing light spectroscopy (including absorbance, fluorescence and scattering measurements) on a liquid sample in microfluidic devices is disclosed. The optical cell comprises an inlaid sheet having an opaque material inlaid in a clear material, and a sensing channel that crosses the clear material and the opaque material provides a fluidic path for the liquid sample and an optical path for probe light. Integral optical windows crossing a clear-opaque material interface permit light coupling into and out of the sensing channel, and thus light transmission through the sensing channel is almost entirely isolated from background light interference. A microfluidic chip comprising one or more optical cells is also disclosed. The optical cells may have different lengths of sensing channels, and may be optically and fluidly coupled. A method of manufacturing an optical cell in a microfluidic chip is also disclosed.

Abstract: A variable magnification optical system consists of, in order from an object side to an image side, a first lens group, a second lens group, and a subsequent lens group. The variable magnification optical system satisfies a predetermined conditional expression for a partial dispersion ratio related to F line, C line, and a wavelength of 1970.09 nm, a d-line back focus of the variable magnification optical system at a telephoto end, a back focus in any one wavelength from a wavelength of 1300 nm to a wavelength of 2325.42 nm at the telephoto end, and a d-line focal length of the variable magnification optical system at the telephoto end.

Abstract: Infrared-transparent and damage-resistant polymer optics with LWIR and/or MWIR transparency are provided. Some variations provide an optic containing at least 50 wt % of an infrared-transparent polymer, wherein the infrared-transparent polymer has a carbon-free polymer backbone, wherein the optic is characterized by at least 80% average transmission of radiation over a wavenumber band with cumulative wavenumber width of at least 1000 cm?1 contained within wavelengths from 3.1 ?m to 5 ?m and/or from 8.1 ?m to 12 ?m, and wherein the average transmission is defined as the percentage ratio of radiation intensity through an optic thickness of 25 microns divided by incident radiation intensity. Many polymer compositions and pendant groups are disclosed for use in the polymer optics.

Abstract: A lens holding structure, comprising a first holding member, a first lens disposed ahead of the first holding member, a second lens disposed ahead of the first lens, a second holding member disposed ahead of the second lens, and a fixing unit that fixes the first holding member and the second holding member in a state of holding the first lens and the second lens between the first holding member and the second holding member, wherein the first lens and the second lens are held between the first holding member and the second holding member in a state of the optical surface of the second lens being surface-contacted with the optical surface of the first lens.

Abstract: A light based skin treatment device comprises a laser light source for providing a pulsed incident light beam for treating skin by laser induced optical breakdown of hair or skin tissue. In one arrangement, a focusing system has a pre-focusing lens for increasing the convergence of the an incident light beam and a skin contact lens having convex light input and light exit surfaces. The focal spot position is controlled by adjusting a spacing between the pre-focusing lens and the skin contact lens. In another arrangement, there is an adjustable lens system before an adjustable focusing system for providing compensation for aberration in the focusing system.

Abstract: An optical imaging system includes lenses. A prism is disposed adjacent to a first lens of the lenses and a second lens of the lenses, and is configured to refract light from the first lens to the second lens. A reflecting member is disposed adjacent to a fifth lens of the lenses and an imaging plane, and is configured to reflect light from the fifth lens to the imaging plane.

Abstract: A method for producing a reactive intermediate composition, including: reacting a substituted phthalic anhydride of the formula (I) with a diamine of the formula H2N—R—NH2 in the presence of an aromatic dianhydride in an amount of 10 to 50 mole percent based on the total moles of anhydride functionality in the reaction; wherein the reacting is conducted in an aprotic solvent in a reactor, under conditions effective to produce the reactive intermediate composition; and wherein X comprises a halogen or a nitro group, and R comprises a C6-36 aromatic hydrocarbon group or a halogenated derivative thereof, a straight or branched chain C2-20 alkylene or a halogenated derivative thereof, or a C3-8 cycloalkylene or a halogenated derivative thereof.

Abstract: A high magnification MWIR continuous zoom optical system is described herein that consists of the following components: a front detachable extender group, a fixed group for focusing incoming radiation, three moving groups for zooming and generating an intermediate image and a relay group. The mentioned optical system has the ability to work with MWIR radiation (3-5 ?m) and generate a thermal image from the gathered radiation. The system also has the ability to zoom continuously in a wide variable focal length range with a high magnification ratio of 20×. With the use of a cooled detector, the combined system allows its user to be able to receive high quality thermal images in all FOV configurations.

Abstract: Systems and methods disclosed herein include an optical blocking structure that may include a frame defining an aperture, first and second elongate structural members each comprising first and second ends such that the first and second elongate structural members may be connected at their first ends to opposite sides of the aperture, and further such that the first and second elongate structural members may extend from the frame parallel to and in the same direction as one another; and an optically opaque blocking member positioned to extend between the respective second ends of the first and second blocking members.

Abstract: A projection lens assembly is provided. The projection lens assembly includes sequentially from a source-side to an image-side along an optical axis: a first lens and a second lens. The first lens has a negative refractive power, a source-side surface of the first lens is a concave surface, and an image-side surface of the first lens is a convex surface. The second lens has a positive refractive power, and an image-side surface of the second lens is a convex surface.

Abstract: An integrated optical assembly comprises an optics mount, an optical element comprising material that is optically transparent, the optical element molded in the optics mount, and an optical aperture wherein the optical aperture is secured in fixed position with respect to the optics mount and the transparent optical element.

Abstract: The disclosed method may include (1) providing, from a display, an image to an eye by way of a lens assembly on an optical path between the display and the eye, wherein the lens assembly includes (a) a first liquid crystal lens providing a first electronically controllable cylindrical power, oriented along a first constant axis, in response to a first signal and (b) a second liquid crystal lens providing a second electronically controllable cylindrical power, oriented along a second constant axis that is rotationally offset from the first constant axis, in response to a second signal, (2) determining, based on information indicating cylindrical power and cylindrical axis components, the electronically controllable cylindrical powers that result in providing the cylindrical power component, oriented along the cylindrical axis component, and (3) generating, based on the electronically controllable cylindrical powers, the signals. Various other systems and methods are also disclosed.

Abstract: An optical image capturing system is provided. In order from an object side to an image side, the optical image capturing system includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. At least one lens among the first lens to the fifth lens has positive refractive power. The sixth lens may have negative refractive power and an object side and an image side thereof are aspherical wherein at least one surface of the sixth lens has an inflection point. The optical image capturing system has six lenses with refractive power. When meeting some certain conditions, the optical image capturing system may have outstanding light-gathering ability and an adjustment ability about the optical path in order to elevate the image quality.

Abstract: According to certain examples a spectrometer module for use in an imaging spectrometer includes a monolithic spectrometer body component made of an immersion material and including three mirrored surfaces configured to form a reflective triplet having an optical path immersed within the immersion material, the reflective triplet configured to receive incident optical radiation from an entrance face of the monolithic spectrometer body component and reflect the incident optical radiation along the optical path, and a dispersive element configured to receive and disperse the incident optical radiation reflected from the reflective triplet to provide dispersed optical radiation. The reflective triplet is configured to receive the dispersed optical radiation from the dispersive element and to reflect the dispersed optical radiation along the optical path to an exit face of the monolithic spectrometer body component.

Abstract: A dual-band refractive inverse telephoto lens system configured for mid-wave infrared (MWIR) and long-wave infrared (LWIR) operation. In certain examples the dual-band refractive inverse telephoto lens system includes first, second, third, and fourth lenses, each constructed from a material that is optically transparent in the mid-wave infrared and long-wave infrared spectral bands, and has an external pupil coincident with an aperture stop of the refractive inverse telephoto lens system, the aperture stop being located between the first, second, third, and fourth lenses and the infrared imaging detector to allow for 100% cold shielding.

Abstract: Provided is an optical system including, in order from an object side to an image side: a first lens having a positive refractive power and having a meniscus shape with a convex surface facing the object side; and a second lens having a positive refractive power and having a meniscus shape with a convex surface facing the object side, wherein the first lens is made of a silicon material, wherein the second lens is made of one of a silicon material and a germanium material, and wherein a focal length of the entire optical system and a distance on an optical axis between the first lens and the second lens are each appropriately set.

Abstract: An optical lens includes a first lens group having negative refractive power, a second lens group having positive refractive power, and an aperture stop disposed between the first lens group and the second lens group. A total number of lenses of the two lens groups is less than 9. The first lens group has at least three lenses with refractive power and at least one aspheric lens. The second lens group has at least three lenses with refractive power and at least one aspheric lens. The first lens group includes a lens having positive refractive power and an Abbe number of smaller than 20.

Abstract: An annular optical element assembly having a central axis includes a first annular optical element, a second annular optical element and a light blocking sheet. The first annular optical element includes a first central opening, a first axial connecting structure and a first inner receiving surface. The second annular optical element includes a second central opening, a second axial connecting structure and a second inner receiving surface. The second inner receiving surface surrounds the second central opening, wherein the second inner receiving surface is closer to the central axis than a second axial connecting surface is to the central axis, the second inner receiving surface is vertical to the central axis, and the first inner receiving surface and the second inner receiving surface are corresponding and not connected to each other for defining a receiving space.

Abstract: According to an embodiment, a method for producing depth information comprises obtaining a plurality of images of an object from a plurality of lens modules, the plurality of images including at least two monochromatic images forming a monochromatic stereo image, producing two complemented monochromatic images by performing a complementary image enhancing process on at least part of the two monochromatic images, the complementary image enhancing process including comparing the plurality of images with each of the two monochromatic images and increasing a resolution of each of the two monochromatic images using an image having a higher resolution in the at least part, selecting a region of interest of the object from the two complemented monochromatic images, and calculating a depth of the region of interest by stereo-matching the two complemented monochromatic images.

Abstract: A layer system includes at least one stack of successive multilayers, wherein each multilayer includes a first partial layer with a first optical thickness and a second partial layer with a second optical thickness that is different from the first optical thickness. The multilayer has optical characteristics that are specified depending on a parameter which is a function of a ratio of quotients of the optical thickness of a partial layer with higher refractive characteristics and the optical thickness of a partial layer with lower refractive characteristics of the respective multilayers, wherein the index i denotes the order of the successive multilayers in the stack. The product of a reflectivity of the stack of multilayers and the parameter is less than for an anti-reflection and/or anti-reflective effect of the stack of multilayers, or is greater than or equal to 1 for a mirroring. An optical element may include a layer system and a method for producing such a layer system.

Abstract: The invention discloses a three-piece optical lens for capturing image and a three-piece optical module for capturing image. In order from an object side to an image side, the optical lens along the optical axis comprises a first lens with positive refractive power; a second lens with refractive power; and a third lens with refractive power; and at least one of the image-side surface and object-side surface of each of the three lenses are aspheric. The optical lens can increase aperture value and improve the imaging quality for use in compact cameras.

Abstract: Disclosed is a system and method for using visible light communication (“VLC”) to perform indoor position location. Through use of a system and method configured as set forth herein, the position of any appropriately marked person or item may be found indoors using data interconnected modules that communicate with one another via RF and visible light. A mobile receiver in the form of a tag or badge attached to the person or item to be tracked receives a VLC signal from a plurality of lighting modules, and transmits back to a mesh network formed by the modules the data it received to determine the tag's or badge's physical position with respect to the individual network modules.

Abstract: An optical lens assembly, which has an optical axis, includes, at least one dual molded lens element having two plastic parts with different colors. The dual molded lens element includes a transparent portion and a light absorbing portion, wherein the transparent portion has an optical effective region. The dual molded lens element has an outer diameter surface connecting a first side surface and a second side surface of the dual molded lens element, the transparent portion is arranged from an optical effective region of the dual molded lens element to the outer diameter surface and surrounds the dual molded lens element, thus the transparent portion is a part of the outer diameter surface, and the light absorbing portion is located on one of the first side surface and the second side surface of the dual molded lens element.

Abstract: Aspects and embodiments are generally directed to compact anamorphic refractive objective lens assemblies. In one example, a refractive objective lens assembly includes a passively athermal anamorphic lens group including at least a first cylindrical lens having a surface optically powered in a first dimension, the first anamorphic lens group positioned to receive thermal infrared radiation, a focus cell positioned to receive the radiation from the anamorphic lens group, the focus cell including a first group of lenses each having a rotationally symmetric surface optically powered in the first dimension and a second dimension orthogonal to the first dimension, a relay lens group positioned receive the radiation from the focus cell, the relay lens group including a second group of lenses each having a rotationally symmetric surface optically powered in both the first and second dimensions, and a dewar assembly including a cold stop and an optical detector.

Abstract: An imaging lens for use with an operational waveband over any subset of 7.5-13.5 ?m may include a first optical element of a first high-index material and a second optical element of a second high-index material, that may have a refractive index greater than 2.2 in the operational waveband, an absorption per mm of less than 75% in the operational waveband, and an absorption per mm of greater than 75% in a visible waveband of 400-650 nm. Optically powered surfaces of the imaging lens may include a sag across their respective clear apertures that are less than 10% of a largest clear aperture of the imaging lens. Respective maximum peak to peak thicknesses of the first and second optical elements may be similar in size, for example within 15 percent of each other. Ratios of maximum peak to peak thickness to clear aperture and, separately, to sag are also provided.

Abstract: An optics arrangement for a solid immersion lens (SIL) is disclosed. The arrangement enables the SIL to freely tilt. The arrangement includes a SIL having an optical axis extending from an engaging surface and a rear surface of the SIL; a SIL housing having a cavity configured to accept the SIL therein while allowing the SIL to freely tilt within the cavity, wherein the cavity includes a hole positioned such that the optical axis passes there-through, to thereby allow light collected by the SIL to propagate to an objective lens; and, a SIL retainer attached to the SIL housing and configured to prevent the SIL from exiting the cavity.

Abstract: A vehicular projection system includes plural information collectors, a time-division multiplexing device and a projection mechanism. The plural information collectors are used for outputting driving information. The time-division multiplexing device includes plural wireless transmission modules. The time-division multiplexing device determines the transmitting sequence of plural information collectors according to the receiving sequence of wireless transmission requests from the plural information collectors. Moreover, the time-division multiplexing device determines the suitable wireless transmission modules according to the file properties of the driving information and the wireless transmission capabilities of the plural information collectors. Since the plural information collectors can simultaneously transmit driving information to the time-division multiplexing device through different wireless transmission modules, the wireless transmission efficiency is enhanced.

Abstract: The disclosure relates to infrared achromatic and athermalized narrow-field arrangements without any mechanical compensation mechanism realized by a single convergent front lens and a single divergent correcting lens. The long back focal length allows for cooled and uncooled detectors, different detector sizes, wavebands, and housing materials. A high resolution is achieved with fast f-numbers below f/2.0.

Abstract: A display includes a stretchable display panel, an optical unit that transmits an image displayed on the display panel for image formation, a mechanical unit that changes a physical shape of the display panel in order to compensate a distortion aberration due to the optical unit, and a control unit that drives the display panel in response to an image source signal.

Abstract: Ophthalmic lenses and light filters containing special additives that have fluorescence emission in the near infrared region of wavelengths—in order to enhance phototherapy for the human eye when it is exposed to sunlight and artificial lighting.

Abstract: An apparatus and method improve sight. The apparatus includes a first sight configured to view a scene. A second sight is configured to alter content representative of the scene in a first manner to form first altered content. A third sight is configured to alter content representative of the scene in a second manner to form second altered content. An image combiner is configured to combine the second altered content with the first altered content to form combined altered scene content.

Abstract: A five-piece optical lens for capturing image and a five-piece optical module for capturing image, along the optical axis in order from an object side to an image side, include a first lens with refractive power having an object-side surface which can be convex; a second lens with negative refractive power; a third lens with positive refractive power; a fourth lens with positive refractive power; and a fifth lens which can have negative refractive power, wherein an image-side surface thereof can be concave, and at least one surface of the fifth lens has an inflection point; both surfaces of each of the five lenses are aspheric. The optical lens can increase aperture value and improve the imaging quality for use in compact cameras.

Abstract: Techniques are disclosed for providing an optical assembly to provide stereoscopic images of a reflected laser spot to a camera for wind measurement. According to certain embodiments of the invention, an optical assembly can include left and right (or first and second) subassemblies having lens groups and reflective elements that cause light traveling left and right subassemblies to follow similar paths to focus on respective left and right portions of a camera. The camera can then use left and right images of reflected laser light to determine wind based on turbulence patterns in the left and right images.

Abstract: Multi-spectral filter elements and methods of formation are disclosed. Each multi-spectral filter element may include a plurality of sub-filters that are, in some examples, each adapted to respond to electromagnetic radiation within respective ones of a plurality of spectral bands. A method example includes forming an optical cavity layer. Volume of the optical cavity layer can be reduced in at least N?1 number of spatial regions. The reducing may include a number of selective removal steps equal to the binary logarithm function Log2 N. In this example, each spatial region corresponds to a respective one of the plurality sub-filters. The plurality of sub-filters includes at least N sub-filters. In particular examples, the respective ones of the plurality of spectral bands may be at least partially discrete with respect to each other.

Abstract: There is provided an infrared optical system includes a light collecting lens having a curved light collecting surface for collecting infrared light incident from an object side, the lens being made of resin having a stepped shape being gradually deeper from periphery to center; and an optical path length correction element for correcting a difference in an optical path length produced by the stepped shape of the light collecting lens. The above-described stepped shape is provided to allow the lens to be thinner than the lens having the plano-convex shape. In other words, the infrared transmittance of the optical system is improved. In addition, the optical path length correction element can correct a difference in an optical path length produced by the stepped shape of the light collecting lens.

Abstract: A five-piece optical lens for capturing image and a five-piece optical module for capturing image, along the optical axis in order from an object side to an image side, include a first lens with negative refractive power having an object-side surface which can be convex; a second lens with refractive power; a third lens with refractive power; a fourth lens with refractive power; and a fifth lens which can have negative refractive power, wherein an image-side surface thereof can be concave, and at least one surface of the fifth lens has an inflection point; both surfaces of each of the five lenses are aspheric. The optical lens can increase aperture value and improve the imaging quality for use in compact cameras.

Abstract: An infrared imaging system used for infrared rays of wavelength of 5 micrometers or greater, the system including, from the object side to the image side, an aperture, a lens made of synthetic resin and an imaging element, the object side surface of the lens being convex to the object side in the paraxial area, wherein F-number of the system is 1.4 or smaller.

Abstract: The present invention provides a signal transmission method and device. The device includes: a transmitting device, configured to transmit a first signal to an opposite terminal; and a receiving device, configured to receive a second signal transmitted by the opposite terminal, where a frequency of the first signal is different from a frequency of the second signal, and the frequency of the first signal and/or the frequency of the second signal are/is in a frequency band of visible light. The present invention resolves a problem in a related technology that poor reliability of uplink and downlink signal transmission is caused when signals of a same frequency are used for uplink and downlink transmission, and provides a beneficial effect of improving reliability of uplink and downlink signal transmission.

Abstract: A five-piece optical lens for capturing image and a five-piece optical module for capturing image, along the optical axis in order from an object side to an image side, include a first lens with positive refractive power having a convex object-side surface; a second lens with refractive power; a third lens with refractive power; a fourth lens with refractive power; and a fifth lens with negative refractive power; and at least one of the image-side surface and object-side surface of each of the five lens elements are aspheric. The optical lens can increase aperture value and improve the imagining quality for use in compact cameras.

Abstract: A five-piece optical lens for capturing image and a five-piece optical module for capturing image, along the optical axis in order from an object side to an image side, include a first lens with positive refractive power having a convex object-side surface; a second lens with refractive power; a third lens with refractive power; a fourth lens with refractive power; and a fifth lens with negative refractive power; and at least one of the image-side surface and object-side surface of each of the five lens elements are aspheric. The optical lens can increase aperture value and improve the imaging quality for use in compact cameras.

Abstract: An object of the present invention is to provide an optical system for an infrared ray which can provide a bright image, and can be applied to fixed focal length lenses among wide-angle to medium-telephoto. To achieve the object, the optical system for an infrared ray is constituted by a first lens having negative refractive power and a second lens having positive refractive power, these are arranged sequentially from an object side, wherein both the first lens and the second lens are made of an infrared transmitting material that transmits a light beam in an infrared wavelength range of 3 micron-meters or more to 14 micron-meters or less, and at least one of the lenses is made of an infrared transmitting material excluding germanium.

Abstract: A five-piece optical lens for capturing image and a five-piece optical module for capturing image, along the optical axis in order from an object side to an image side, include a first lens with positive refractive power, wherein an object-side surface thereof can be convex; a second lens with refractive power; a third lens with refractive power; a fourth lens with refractive power; and a fifth lens with negative refractive power, wherein an image-side surface can be concave, and at least one surface of the fifth lens has an inflection point; both surfaces of each of the five lenses are aspheric. The optical lens can increase aperture value and improve the imaging quality for use in compact cameras.

Abstract: Techniques are disclosed for providing an optical assembly to provide stereoscopic images of a reflected laser spot to a camera for wind measurement. According to certain embodiments of the invention, an optical assembly can include left and right (or first and second) subassemblies having lens groups and reflective elements that cause light traveling left and right subassemblies to follow similar paths to focus on respective left and right portions of a camera. The camera can then use left and right images of reflected laser light to determine wind based on turbulence patterns in the left and right images.

Abstract: An image pick-up apparatus includes an imaging optical system including a plurality of lenses and a diaphragm arranged between the lenses, the imaging optical system forming an image on an image surface; and an image sensor that detects the image formed on the image surface. The imaging optical system includes a front lens group on an object side with respect to the diaphragm, and a rear lens group on the image surface side with respect to the diaphragm. A lens surface having the highest power in the front lens group and a lens surface having the highest power in the rear lens group are concentric surfaces. The front lens group includes a plano-concave lens whose light-exiting-side surface has a concave surface and whose light-incident-side surface has power ?r that satisfies the following expression: - 0.05 ? ? ? ? r ? ? ? o ? 0.05 where ?o is the power of the entire imaging optical system.

Abstract: An infrared imaging optical system for focusing infrared radiation on an infrared detector, including: a front lens group having a negative optical power to receive infrared radiation and including a first front lens and a second front lens each with at least one aspherical surface; an intermediate lens group that receives the infrared radiation from the front lens group and includes a first intermediate lens, a second intermediate lens, and a third intermediate lens each with at least one aspherical surface; and a rear lens group having positive optical power, wherein the rear lens group receives the infrared radiation from the intermediate lens group and includes a first rear lens and a second rear lens each with at least one aspherical surface, and a third rear lens, wherein the imaging optical system has a stop between the rear lens group and a focal plane at said infrared detector.

Abstract: An imaging lens for use with an operational waveband over any subset of 7.5-13.5 ?m may include a first optical element of a first high-index material and a second optical element of a second high-index material. At least two surfaces of the first and second optical elements may be optically powered surfaces. A largest clear aperture of all optically powered surfaces may not exceed a diameter of an image circle of the imaging lens corresponding to a field of view of 55 degrees or greater by more than 30%. The first and second high-index materials may have a refractive index greater than 2.2 in the operational waveband, an absorption per mm of less than 75% in the operational waveband, and an absorption per mm of greater than 75% in a visible waveband of 400-650 nm.

Abstract: An imaging lens includes, from the object side to the image side, an aperture stop, a first lens with positive refractive power having a convex object-side surface near an optical axis, a second lens with positive refractive power having a convex image-side surface near the axis, a third lens with positive refractive power having a convex image-side surface near the axis, and a fourth lens with negative refractive power having a concave image-side surface near the axis, wherein all lens surfaces are aspheric, all lenses are made of plastic material, a diffractive optical surface is formed on at least one of the lens surfaces from the first lens image-side surface to the second lens image-side surface, and at least one of the three positive lenses satisfies 1.58<Ndi where Ndi is the refractive index of the i-th positive lens at the d-ray.

Abstract: An optical assembly for a point action camera with a wide field of view has multiple lens elements configured to provide a field of view in excess of 150 degrees. One or more lens elements has an aspheric surface with an approximately 30 microns or less sag and an approximately 25 microns/millimeter or less aspheric sag slope.

Abstract: An endoscope tip part has impact resistance even when applied to a thin endoscope, and the light distribution characteristics thereof can be improved even at a wide angle of view. An endoscope tip part includes a tip part main body that is attached to the tip of an insertion section of an endoscope and a positive-power transparent-plastic tip lens that is integrated with the tip part main body through two-color molding. The tip lens is a lens that is located closest to an object, among optical elements constituting an illumination optical system of the endoscope, and the tip part main body is provided with an insertion hole into which two positive-power rear lenses that will be disposed behind the tip lens are inserted.