Статті в журналах з теми "Flat-convex lens"

Anti-reflection coatings (ARCs) from the cornea nipple array of the moth-eye remarkably suppress the Fresnel reflection at the interface in broadband wavelength ranges. ARCs on flat glass have been studied to enhance the optical transmittance. However, little research on the implementation of ARCs on curved optical lenses, which are the core element in imaging devices, has been reported. Here, we report double-sided, bio-inspired ARCs on bi-convex lenses with high uniformity. We theoretically optimize the nanostructure geometry, such as the height, period, and morphology, since an anti-reflection property results from the gradually changed effective refractive index by the geometry of nanostructures. In an experiment, the transmittance of an ARCs lens increases up to 10% for a broadband spectrum without distortion in spot size and focal length. Moreover, we demonstrate ~30% improved transmittance of an imaging system composed of three bi-convex lenses, in series with double-sided ARCs (DARCs).

Abstract A flat telescope (FTS), which incorporates an all-dielectric metasurface doublet (MD) based on hydrogenated amorphous silicon nanoposts, is proposed and demonstrated to achieve flexibly magnified angular beam steering that is sensitive to both light polarization and deflection direction. Specifically, for transverse-electric-polarized incident beams, the MD exhibits deflection magnification factors of +5 and +2, while for transverse magnetic polarization, the beam is steered in reverse to yield magnification factors of −5 and −2 in the horizontal and vertical directions, respectively. The proposed MD comprises cascaded metalenses, which can invoke polarization-selective transmission phases. The MD which emulates a set of convex and concave lenses renders positively increased beam deflection, whereas the case corresponding to a pair of convex lenses facilitates negatively amplified beam deflection. The essential phase profiles required for embodying the MD are efficiently extracted from its geometric lens counterpart. Furthermore, the implemented FTS, operating in the vicinity of a 1550 nm wavelength, can successfully enable enhanced beam steering by facilitating polarization-sensitive bidirectional deflection amplifications. The proposed FTS can be applied in the development of a miniaturized light detection and ranging system, where the beam scanning range can be effectively expanded in two dimensions.

Near infrared spectroscopy is an optical imaging technique which offers a non-invasive, portable, and low-cost method for continuously measuring the oxygenation of tissues. In particular, it can provide the brain activation through measuring the blood oxygenation and blood volume in the cortex. Understanding and then improving the spatial and depth sensitivity of near infrared spectroscopy measurements to brain tissue are essential for designing experiments as well as interpreting research findings. In this study, we investigate the effect of applying two common light beam profiles including Uniform and Gaussian on the penetration depth of an LED-based near infrared spectroscopy. In this regard, two Gaussian profiles were produced by adjusting plano-convex and bi-convex lenses and the Uniform profile was provided by applying a flat lens. Two experiments were conducted in this study. First, a simulation experiment was carried out based on scanning the intra space of a liquid phantom by using static and pulsating absorbers to compare the penetration depth of the configurations applied on the LED-based near infrared spectroscopy with that of a laser-based near infrared spectroscopy. Second, to show the feasibility of the best proposed configuration applied, an in vivo experiment of stress assessment has been performed and its results have been compared with that results obtained by laser one. The results showed that the LED-based near infrared spectroscopy equipped with bi-convex lens provides a penetration depth and hence quality measurements of near infrared spectroscopy and its extracted heart rate variability signals as well as laser-based near infrared spectroscopy especially in the application of stress assessment.

The structural organization and protein composition of lens fiber junctions isolated from adult bovine and calf lenses were studied using combined electron microscopy, immunolocalization with monoclonal and polyclonal anti-MIP and anti-MP70 (two putative gap junction-forming proteins), and freeze-fracture and label-fracture methods. The major intrinsic protein of lens plasma membranes (MIP) was localized in single membranes and in an extensive network of junctions having flat and undulating surface topologies. In wavy junctions, polyclonal and monoclonal anti-MIPs labeled only the cytoplasmic surface of the convex membrane of the junction. Label-fracture experiments demonstrated that the convex membrane contained MIP arranged in tetragonal arrays 6-7 nm in unit cell dimension. The apposing concave membrane of the junction displayed fracture faces without intramembrane particles or pits. Therefore, wavy junctions are asymmetric structures composed of MIP crystals abutted against particle-free membranes. In thin junctions, anti-MIP labeled the cytoplasmic surfaces of both apposing membranes with varying degrees of asymmetry. In thin junctions, MIP was found organized in both small clusters and single membranes. These small clusters also abut against particle-free apposing membranes, probably in a staggered or checkerboard pattern. Thus, the structure of thin and wavy junctions differed only in the extent of crystallization of MIP, a property that can explain why this protein can produce two different antibody-labeling patterns. A conclusion of this study is that wavy and thin junctions do not contain coaxially aligned channels, and, in these junctions, MIP is unlikely to form gap junction-like channels. We suggest MIP may behave as an intercellular adhesion protein which can also act as a volume-regulating channel to collapse the lens extracellular space. Junctions constructed of MP70 have a wider overall thickness (18-20 nm) and are abundant in the cortical regions of the lens. A monoclonal antibody raised against this protein labeled these thicker junctions on the cytoplasmic surfaces of both apposing membranes. Thick junctions also contained isolated clusters of MIP inside the plaques of MP70. The role of thick junctions in lens physiology remains to be determined.

The method of manufacturing and the results of studies of a lens corrector that converts a spherical diverging front into a plane one and is intended for studying flat surfaces as part of an interferometer with a diffraction comparison wave is described. A feature of the corrector is the use of an aspherical convex surface with a maximum deviation of ∼200 μm from the nearest sphere. The first experimental results are presented, indicating the prospects for using ion-beam processing to improve the quality of the wavefront. After the procedure of ion-beam processing, the aberrations over the entire aperture of the corrector decreased by more than 4 times and amounted to the parameter of the height difference PV = 207 nm (∼λ/3) and RMS = 19.2 nm (∼λ /33). On an area with a diameter of 80%, the aberrations fell to the nanometer level: PV = 65 nm (∼λ/10) and RMS = 8.3 nm (∼λ/76).

In order to improve upon the inconvenient and complicated contemporary analytic techniques employed for optical systems, this paper investigates two important optical topics: (1) the determination of light ray paths and (2) sensitivity analysis of light path parameters with respect to the light source location for occasions when light rays cross medium boundary surfaces. To this end, the traditional laws of reflection and refraction are reformulated in terms of revolution geometry. This results in a set of laws much simpler than the original, suitable for use in mathematical modeling to determine light paths and system sensitivity from location of the light source, optical component location, the equation of the optical component’s surface curve, and the refractive index. Ray tracing and sensitivity analysis of the two most popular boundary surfaces, flat and spherical, are presented as examples. In order to illustrate experimentally the integration of these boundary surfaces into optical systems, an optical measurement system for measuring surface height and orientation, containing a beam splitter and a bi-convex lens, was built. Agreement between the experimental optical system’s performance and the theoretical predictions yielded by the proposed method are excellent. [S1087-1357(00)01501-X]

Glaucoma is a leading cause of irreversible blindness worldwide. Among different types of glaucoma, irreversible bilateral visual impairment is more common in primary angle closure glaucoma (PACG) patients. PACG and cataract often coexist and are both more prevalent among the elderly population, being rare in children and young adults. Here, we discuss the case of a 39-year-old Caucasian woman with unilateral PACG associated with cataract. The patient presented with a several-day history of left sided headache, decreased and blurred vision as well as pain and redness of the left eye (LE). She reported similar episodes in the previous year. Visual acuity (VA) of the LE was limited to counting fingers and intra-ocular pressure (IOP) of the LE was 42 mmHg. Anterior segment examination of the LE revealed: edematous cornea, a peripheral anterior chamber depth corresponding to Van Herick’s grade 0, mid-dilated pupil and lens opacities with visible glaukomflecken. Gonioscopic evaluation revealed iridotrabecular contact for 360º, no visible angle structures and a flat–mild convex iris contour. Spectral domain optical coherence tomography suggested only a thinning of neuro-retinal rim at the lower pole. Following treatment of the initial symptoms, phacoemulsification with intra-ocular lens implant was performed. IOP improved and no IOP-lowering medication was required. The patient was monitored for VA, IOP, field of vision changes, and optic disc evaluation every six months for 2 years and no glaucomatous change occurred. The patient also denied ocular symptoms during this period. This case supports the effectiveness of early phacoemulsification in the IOP control in patients with PACG.

Glaucoma is a leading cause of irreversible blindness in the world, second only to cataract. Among different types of glaucoma, irreversible bilateral visual impairment is more common in primary angle closure glaucoma (PACG) patients. PACG and cataract often coexist and are both more prevalent among the elderly population, being rare in children and young adults. Here, we discuss the case of a 39-year-old Caucasian woman with unilateral PACG associated with cataract. The patient presented with a several-day history of left sided headache, decreased and blurred vision as well as pain and redness of the left eye (LE). She reported similar episodes in the previous year. Visual acuity (VA) of the LE was limited to counting fingers and intra-ocular pressure (IOP) of the LE was 42 mmHg. Anterior segment examination of the LE revealed: edematous cornea, a peripheral anterior chamber depth corresponding to Van Herick’s grade 0, mid-dilated pupil and lens opacities with visible glaukomflecken. Gonioscopic evaluation revealed iridotrabecular contact for 360º, no visible angle structures and a flat–mild convex iris contour. The digital image of the optic disc suggested only a thinning of neuro-retinal rim at the lower pole. Following treatment of the initial symptoms, phacoemulsification with intra-ocular lens implant was performed. IOP improved and no IOP-lowering medication was required. The patient was monitored for VA, IOP, field of vision changes, and optic disc evaluation every six months for 2 years and no glaucomatous change occurred. The patient also denied ocular symptoms during this period. This case supports the effectiveness of early phacoemulsification in the IOP control in patients with PACG.

The paper presents the technology of obtaining flat-conical lenses (axicons) by the method of free grinding a work-piece to a flat tool through a layer of abrasive suspension. For this, theoretical and experimental studies of the regularities of stock removal from the base of the cone and its lateral surface have been carried out. The processing modes have been identified that ensure both uniform operation of the flat surface of the part and enhanced removal of the allowance in the edge or central zone of this surface. During the study of the processing of the conical surface, the set-up parameters of the technological equipment have been established, at which there is a minimum deviation of the generatrix of the cone from straightness and maximum productivity of the process. The stages of processing conical lenses are proposed, which allow to assign the optimal sequence of operations in the manufacture of this type of parts from blanks of a cylindrical shape in cases where the ratio of the height of the cone to the diameter of its base H/d £ 0.5. The main stages of processing include: grinding of the bases of cylindrical blanks with maintaining their mutual parallelism with a given accuracy; polishing one of the cylinder bases to achieve the required roughness and deviation from non-flatness; fastening a cylindrical blank to an auxiliary plane-parallel glass plate using molecular cohesion forces; mechanical fastening of a cylindrical work-piece with a collet adapter mandrel for a plane-parallel glass plate; applying the nearest sphere to the second base of the cylindrical blank; drawing a conical surface on the spherical part of a plano-convex lens; grinding and polishing the conical surface to achieve the required roughness and straightness of the cone generatrix. The degree of efficiency of the setup parameters of the machine has been revealed depending on the technological heredity of the work-piece from the point of view of the distribution of the allowance to be removed over the machined surface.

We demonstrate that the concave-convex circular composite structure sidewall prepared by inductively coupled plasma (ICP) etching is an effective approach to increase the light efficiency without deteriorating the electrical characteristics for micro light-emitting diodes (LEDs). The saturated light output power of the device using the concave-convex circular composite structure sidewalls with a radius of 2 μm is 39.75 mW, an improvement of 7.2% compared with that of the device using flat sidewalls. The enhanced light output characteristics are primarily attributed to the increased photon emitting due by decreasing the total internal reflection without losing the active region area.

Similar to other leaf beetles, rosemary beetles Chrysolina americana exhibit a distinct sexual dimorphism in tarsal attachment setae. Setal discoid terminals occur only in males, and they have been previously associated with a long-term attachment to the female's back (elytra) during copulation and mate guarding. For the first time, we studied living males and females holding to female's elytra. Pull-off force measurements with a custom-made tribometer featuring a self-aligning sample holder confirmed stronger attachment to female elytra compared with glass in both males and females; corresponding to 45 and 30 times the body weight, respectively. In line with previous studies, males generated significantly higher forces than females on convex elytra and flat glass, 1.2 times and 6.8 times, respectively. Convex substrates like elytra seem to improve the attachment ability of rosemary beetles, because they can hold more strongly due to favourable shear angles of legs, tarsi and adhesive setae. A self-aligning sample holder is found to be suitable for running force measurement tests with living biological samples.

This research studies the dynamics and motion control of a biped walking robot with seven degrees of freedom. The main features of the biped robot include variable length legs and a translatable balance weight in the body. The statically stable walking of the biped robot is implemented by maintaining the center-of-gravity (cg) inside the convex region of the supporting foot/feet during both single-support and double-support phases. The dynamically stable walking of the biped robot is realized by maintaining the zero moment point (ZMP), which is the virtual total ground reaction point, within the region of the supporting foot during the single-support phases. An implementation of a prototype biped BR-1 and its experimental walking test results are described. The biped robot is able to walk on an even floor both statically and dynamically. On a flat plane, the biped can walk with a speed of 8 cm/second statically, and 20 cm/second dynamically.

Abstract This paper describes the design methodology for a novel Fresnel lens. The original Fresnel lens is obtained from a plano-convex lens, whose spherical surface is split into a number of divisions (called facets), collapsed onto the flat base. Thus, all the facets of the original Fresnel lens have the same radius as that of the plano-convex lens. The proposed design aims to achieve better ray concentration and reduced spherical aberration than the original Fresnel lens by constructing spherical facets with unequal radii. The centers and radii of facets are constrained so that the ray refracted from the bottom vertex of each facet on one side of the optical axis and the ray refracted from the outer vertex of the corresponding facet on the other side of the optical axis must intersect at the focal plane. The proposed lens design has resulted in a 275% gain in the concentration ratio and a 72.5% reduction in the spherical aberration compared to the original lens of the same aperture diameter and number of facets. The performance of both novel and original Fresnel lenses when used as solar concentrators with a conical coil receiver is evaluated. The novel Fresnel lens led to increased heat gain and resulted in a compact solar collector design.

AbstractWe herein present the results of a study on the novel fabrication process of uniform and homogeneous semiconducting polymer layers, in this case hole-injecting and fluorescent light-emitting layers that were produced by a simple solution-coating process for 3D conformal organic light-emitting diodes (3D OLEDs) on curvilinear surfaces. The solution-coating process used was a newly developed method of vortex-flow-assisted solution-coating with the support of spinning of the coating solution. It is shown that the vortex-flow-assisted spin-coating process can produce high-quality thin films at nanoscale thicknesses by controlling the liquid surface of the coating solutions, which can easily be adjusted by changing the spinning speed, even on complex curvilinear surfaces, i.e., a quasi-omnidirectional coating. This excellent film-forming ability without any serious film defects is mainly due to the reduction of line tension among the solution, air, and the substrate at the contact line due to vortex flows of the coating solution on the substrate during the vortex-spin-coating process. As a proof of concept, we present vortex-spin-coated 3D OLEDs fabricated on bi-convex lens substrates which exhibit excellent device performance with high brightness and current efficiency levels comparable to those of a conventional spin-coated 2D planar OLED on a flat substrate. It is also shown that the EL emission from the 3D OLED on the bi-convex lens substrate exhibits a diffusive Lambertian radiation pattern. The results here demonstrate that the vortex-flow-assisted spin-coating process is a promising approach for producing efficient and reliable next-generation OLEDs for 3D conformal opto-electronics.

AbstractConventional imaging and recognition systems require an extensive amount of data storage, pre-processing, and chip-to-chip communications as well as aberration-proof light focusing with multiple lenses for recognizing an object from massive optical inputs. This is because separate chips (i.e., flat image sensor array, memory device, and CPU) in conjunction with complicated optics should capture, store, and process massive image information independently. In contrast, human vision employs a highly efficient imaging and recognition process. Here, inspired by the human visual recognition system, we present a novel imaging device for efficient image acquisition and data pre-processing by conferring the neuromorphic data processing function on a curved image sensor array. The curved neuromorphic image sensor array is based on a heterostructure of MoS2 and poly(1,3,5-trimethyl-1,3,5-trivinyl cyclotrisiloxane). The curved neuromorphic image sensor array features photon-triggered synaptic plasticity owing to its quasi-linear time-dependent photocurrent generation and prolonged photocurrent decay, originated from charge trapping in the MoS2-organic vertical stack. The curved neuromorphic image sensor array integrated with a plano-convex lens derives a pre-processed image from a set of noisy optical inputs without redundant data storage, processing, and communications as well as without complex optics. The proposed imaging device can substantially improve efficiency of the image acquisition and recognition process, a step forward to the next generation machine vision.

Introduction Explorations of the multimedia game format within cultural studies have been broadly approached from two perspectives: one -- the impact of technologies on user interaction particularly with regard to social implications, and the other -- human computer interactions within the framework of cybercultures. Another approach to understanding or speaking about games within cultural studies is to focus on the game experience as cultural practice -- as an activity or an event. In this article I wish to initiate an exploration of the aesthetics of player space as a distinctive element of the gameplay experience. In doing so I propose that an understanding of aesthetic spatial issues as an element of player interactivity and engagement is important for understanding the cultural practice of adventure gameplay. In approaching these questions, I am focussing on the single-player exploration adventure game in particular Myst and The Crystal Key. In describing these games as adventures I am drawing on Chris Crawford's The Art of Computer Game Design, which although a little dated, focusses on game design as a distinct activity. He brings together a theoretical approach with extensive experience as a game designer himself (Excalibur, Legionnaire, Gossip). Whilst at Atari he also worked with Brenda Laurel, a key theorist in the area of computer design and dramatic structure. Adventure games such as Myst and The Crystal Key might form a sub-genre in Chris Crawford's taxonomy of computer game design. Although they use the main conventions of the adventure game -- essentially a puzzle to be solved with characters within a story context -- the main focus and source of pleasure for the player is exploration, particularly the exploration of worlds or cosmologies. The main gameplay of both games is to travel through worlds solving clues, picking up objects, and interacting with other characters. In Myst the player has to solve the riddle of the world they have entered -- as the CD-ROM insert states "Now you're here, wherever here is, with no option but to explore." The goal, as the player must work out, is to release the father Atrus from prison by bringing magic pages of a book to different locations in the worlds. Hints are offered by broken-up, disrupted video clips shown throughout the game. In The Crystal Key, the player as test pilot has to save a civilisation by finding clues, picking up objects, mending ships and defeating an opponent. The questions foregrounded by a focus on the aesthetics of navigation are: What types of representational context are being set up? What choices have designers made about representational context? How are the players positioned within these spaces? What are the implications for the player's sense of orientation and navigation? Architectural Fabrication For the ancient Greeks, painting was divided into two categories: magalography (the painting of great things) and rhyparography (the painting of small things). Magalography covered mythological and historical scenes, which emphasised architectural settings, the human figure and grand landscapes. Rhyparography referred to still lifes and objects. In adventure games, particularly those that attempt to construct a cosmology such as Myst and The Crystal Key, magalography and rhyparography collide in a mix of architectural monumentality and obsessive detailing of objects. For the ancient Greeks, painting was divided into two categories: magalography (the painting of great things) and rhyparography (the painting of small things). Magalography covered mythological and historical scenes, which emphasised architectural settings, the human figure and grand landscapes. Rhyparography referred to still lifes and objects. In adventure games, particularly those that attempt to construct a cosmology such as Myst and The Crystal Key, magalography and rhyparography collide in a mix of architectural monumentality and obsessive detailing of objects. The creation of a digital architecture in adventure games mimics the Pompeii wall paintings with their interplay of extruded and painted features. In visualising the space of a cosmology, the environment starts to be coded like the urban or built environment with underlying geometry and textured surface or dressing. In The Making of Myst (packaged with the CD-ROM) Chuck Carter, the artist on Myst, outlines the process of creating Myst Island through painting the terrain in grey scale then extruding the features and adding textural render -- a methodology that lends itself to a hybrid of architectural and painted geometry. Examples of external architecture and of internal room design can be viewed online. In the spatial organisation of the murals of Pompeii and later Rome, orthogonals converged towards several vertical axes showing multiple points of view simultaneously. During the high Renaissance, notions of perspective developed into a more formal system known as the construzione legittima or legitimate construction. This assumed a singular position of the on-looker standing in the same place as that occupied by the artist when the painting was constructed. In Myst there is an exaggeration of the underlying structuring technique of the construzione legittima with its emphasis on geometry and mathematics. The player looks down at a slight angle onto the screen from a fixed vantage point and is signified as being within the cosmological expanse, either in off-screen space or as the cursor. Within the cosmology, the island as built environment appears as though viewed through an enlarging lens, creating the precision and coldness of a Piero della Francesca painting. Myst mixes flat and three-dimensional forms of imagery on the same screen -- the flat, sketchy portrayal of the trees of Myst Island exists side-by-side with the monumental architectural buildings and landscape design structures created in Macromodel. This image shows the flat, almost expressionistic trees of Myst Island juxtaposed with a fountain rendered in high detail. This recalls the work of Giotto in the Arena chapel. In Joachim's Dream, objects and buildings have depth, but trees, plants and sky -- the space in-between objects -- is flat. Myst Island conjures up the realm of a magic, realist space with obsolete artefacts, classic architectural styles (the Albert Hall as the domed launch pad, the British Museum as the library, the vernacular cottage in the wood), mechanical wonders, miniature ships, fountains, wells, macabre torture instruments, ziggurat-like towers, symbols and odd numerological codes. Adam Mates describes it as "that beautiful piece of brain-deadening sticky-sweet eye-candy" but more than mere eye-candy or graphic verisimilitude, it is the mix of cultural ingredients and signs that makes Myst an intriguing place to play. The buildings in The Crystal Key, an exploratory adventure game in a similar genre to Myst, celebrate the machine aesthetic and modernism with Buckminster Fuller style geodesic structures, the bombe shape, exposed ducting, glass and steel, interiors with movable room partitions and abstract expressionist decorations. An image of one of these modernist structures is available online. The Crystal Key uses QuickTime VR panoramas to construct the exterior and interior spaces. Different from the sharp detail of Myst's structures, the focus changes from sharp in wide shot to soft focus in close up, with hot-spot objects rendered in trompe l'oeil detail. The Tactility of Objects "The aim of trompe l'oeil -- using the term in its widest sense and applying it to both painting and objects -- is primarily to puzzle and to mystify" (Battersby 19). In the 15th century, Brunelleschi invented a screen with central apparatus in order to obtain exact perspective -- the monocular vision of the camera obscura. During the 17th century, there was a renewed interest in optics by the Dutch artists of the Rembrandt school (inspired by instruments developed for Dutch seafaring ventures), in particular Vermeer, Hoogstraten, de Hooch and Dou. Gerard Dou's painting of a woman chopping onions shows this. These artists were experimenting with interior perspective and trompe l'oeil in order to depict the minutia of the middle-class, domestic interior. Within these luminous interiors, with their receding tiles and domestic furniture, is an elevation of the significance of rhyparography. In the Girl Chopping Onions of 1646 by Gerard Dou the small things are emphasised -- the group of onions, candlestick holder, dead fowl, metal pitcher, and bird cage. Trompe l'oeil as an illusionist strategy is taken up in the worlds of Myst, The Crystal Key and others in the adventure game genre. Traditionally, the fascination of trompe l'oeil rests upon the tension between the actual painting and the scam; the physical structures and the faux painted structures call for the viewer to step closer to wave at a fly or test if the glass had actually broken in the frame. Mirian Milman describes trompe l'oeil painting in the following manner: "the repertory of trompe-l'oeil painting is made up of obsessive elements, it represents a reality immobilised by nails, held in the grip of death, corroded by time, glimpsed through half-open doors or curtains, containing messages that are sometimes unreadable, allusions that are often misunderstood, and a disorder of seemingly familiar and yet remote objects" (105). Her description could be a scene from Myst with in its suggestion of theatricality, rich texture and illusionistic play of riddle or puzzle. In the trompe l'oeil painterly device known as cartellino, niches and recesses in the wall are represented with projecting elements and mock bas-relief. This architectural trickery is simulated in the digital imaging of extruded and painting elements to give depth to an interior or an object. Other techniques common to trompe l'oeil -- doors, shadowy depths and staircases, half opened cupboard, and paintings often with drapes and curtains to suggest a layering of planes -- are used throughout Myst as transition points. In the trompe l'oeil paintings, these transition points were often framed with curtains or drapes that appeared to be from the spectator space -- creating a painting of a painting effect. Myst is rich in this suggestion of worlds within worlds through the framing gesture afforded by windows, doors, picture frames, bookcases and fireplaces. Views from a window -- a distant landscape or a domestic view, a common device for trompe l'oeil -- are used in Myst to represent passageways and transitions onto different levels. Vertical space is critical for extending navigation beyond the horizontal through the terraced landscape -- the tower, antechamber, dungeon, cellars and lifts of the fictional world. Screen shots show the use of the curve, light diffusion and terracing to invite the player. In The Crystal Key vertical space is limited to the extent of the QTVR tilt making navigation more of a horizontal experience. Out-Stilling the Still Dutch and Flemish miniatures of the 17th century give the impression of being viewed from above and through a focussing lens. As Mastai notes: "trompe l'oeil, therefore is not merely a certain kind of still life painting, it should in fact 'out-still' the stillest of still lifes" (156). The intricate detailing of objects rendered in higher resolution than the background elements creates a type of hyper-reality that is used in Myst to emphasise the physicality and actuality of objects. This ultimately enlarges the sense of space between objects and codes them as elements of significance within the gameplay. The obsessive, almost fetishistic, detailed displays of material artefacts recall the curiosity cabinets of Fabritius and Hoogstraten. The mechanical world of Myst replicates the Dutch 17th century fascination with the optical devices of the telescope, the convex mirror and the prism, by coding them as key signifiers/icons in the frame. In his peepshow of 1660, Hoogstraten plays with an enigma and optical illusion of a Dutch domestic interior seen as though through the wrong end of a telescope. Using the anamorphic effect, the image only makes sense from one vantage point -- an effect which has a contemporary counterpart in the digital morphing widely used in adventure games. The use of crumbled or folded paper standing out from the plane surface of the canvas was a recurring motif of the Vanitas trompe l'oeil paintings. The highly detailed representation and organisation of objects in the Vanitas pictures contained the narrative or symbology of a religious or moral tale. (As in this example by Hoogstraten.) In the cosmology of Myst and The Crystal Key, paper contains the narrative of the back-story lovingly represented in scrolls, books and curled paper messages. The entry into Myst is through the pages of an open book, and throughout the game, books occupy a privileged position as holders of stories and secrets that are used to unlock the puzzles of the game. Myst can be read as a Dantesque, labyrinthine journey with its rich tapestry of images, its multi-level historical associations and battle of good and evil. Indeed the developers, brothers Robyn and Rand Miller, had a fertile background to draw on, from a childhood spent travelling to Bible churches with their nondenominational preacher father. The Diorama as System Event The diorama (story in the round) or mechanical exhibit invented by Daguerre in the 19th century created a mini-cosmology with player anticipation, action and narrative. It functioned as a mini-theatre (with the spectator forming the fourth wall), offering a peek into mini-episodes from foreign worlds of experience. The Musée Mechanique in San Francisco has dioramas of the Chinese opium den, party on the captain's boat, French execution scenes and ghostly graveyard episodes amongst its many offerings, including a still showing an upper class dancing party called A Message from the Sea. These function in tandem with other forbidden pleasures of the late 19th century -- public displays of the dead, waxwork museums and kinetescope flip cards with their voyeuristic "What the Butler Saw", and "What the Maid Did on Her Day Off" tropes. Myst, along with The 7th Guest, Doom and Tomb Raider show a similar taste for verisimilitude and the macabre. However, the pre-rendered scenes of Myst and The Crystal Key allow for more diorama like elaborate and embellished details compared to the emphasis on speed in the real-time-rendered graphics of the shoot-'em-ups. In the gameplay of adventure games, animated moments function as rewards or responsive system events: allowing the player to navigate through the seemingly solid wall; enabling curtains to be swung back, passageways to appear, doors to open, bookcases to disappear. These short sequences resemble the techniques used in mechanical dioramas where a coin placed in the slot enables a curtain or doorway to open revealing a miniature narrative or tableau -- the closure of the narrative resulting in the doorway shutting or the curtain being pulled over again. These repeating cycles of contemplation-action-closure offer the player one of the rewards of the puzzle solution. The sense of verisimilitude and immersion in these scenes is underscored by the addition of sound effects (doors slamming, lifts creaking, room atmosphere) and music. Geographic Locomotion Static imagery is the standard backdrop of the navigable space of the cosmology game landscape. Myst used a virtual camera around a virtual set to create a sequence of still camera shots for each point of view. The use of the still image lends itself to a sense of the tableauesque -- the moment frozen in time. These tableauesque moments tend towards the clean and anaesthetic, lacking any evidence of the player's visceral presence or of other human habitation. The player's navigation from one tableau screen to the next takes the form of a 'cyber-leap' or visual jump cut. These jumps -- forward, backwards, up, down, west, east -- follow on from the geographic orientation of the early text-based adventure games. In their graphic form, they reveal a new framing angle or point of view on the scene whilst ignoring the rules of classical continuity editing. Games such as The Crystal Key show the player's movement through space (from one QTVR node to another) by employing a disorientating fast zoom, as though from the perspective of a supercharged wheelchair. Rather than reconciling the player to the state of movement, this technique tends to draw attention to the technologies of the programming apparatus. The Crystal Key sets up a meticulous screen language similar to filmic dramatic conventions then breaks its own conventions by allowing the player to jump out of the crashed spaceship through the still intact window. The landscape in adventure games is always partial, cropped and fragmented. The player has to try and map the geographical relationship of the environment in order to understand where they are and how to proceed (or go back). Examples include selecting the number of marker switches on the island to receive Atrus's message and the orientation of Myst's tower in the library map to obtain key clues. A screenshot shows the arrival point in Myst from the dock. In comprehending the landscape, which has no centre, the player has to create a mental map of the environment by sorting significant connecting elements into chunks of spatial elements similar to a Guy Debord Situationist map. Playing the Flaneur The player in Myst can afford to saunter through the landscape, meandering at a more leisurely pace that would be possible in a competitive shoot-'em-up, behaving as a type of flaneur. The image of the flaneur as described by Baudelaire motions towards fin de siècle decadence, the image of the socially marginal, the dispossessed aristocrat wandering the urban landscape ready for adventure and unusual exploits. This develops into the idea of the artist as observer meandering through city spaces and using the power of memory in evoking what is observed for translation into paintings, writing or poetry. In Myst, the player as flaneur, rather than creating paintings or writing, is scanning the landscape for clues, witnessing objects, possible hints and pick-ups. The numbers in the keypad in the antechamber, the notes from Atrus, the handles on the island marker, the tower in the forest and the miniature ship in the fountain all form part of a mnemomic trompe l'oeil. A screenshot shows the path to the library with one of the island markers and the note from Atrus. In the world of Myst, the player has no avatar presence and wanders around a seemingly unpeopled landscape -- strolling as a tourist venturing into the unknown -- creating and storing a mental map of objects and places. In places these become items for collection -- cultural icons with an emphasised materiality. In The Crystal Key iconography they appear at the bottom of the screen pulsing with relevance when active. A screenshot shows a view to a distant forest with the "pick-ups" at the bottom of the screen. This process of accumulation and synthesis suggests a Surrealist version of Joseph Cornell's strolls around Manhattan -- collecting, shifting and organising objects into significance. In his 1982 taxonomy of game design, Chris Crawford argues that without competition these worlds are not really games at all. That was before the existence of the Myst adventure sub-genre where the pleasures of the flaneur are a particular aspect of the gameplay pleasures outside of the rules of win/loose, combat and dominance. By turning the landscape itself into a pathway of significance signs and symbols, Myst, The Crystal Key and other games in the sub-genre offer different types of pleasures from combat or sport -- the pleasures of the stroll -- the player as observer and cultural explorer. References Battersby, M. Trompe L'Oeil: The Eye Deceived. New York: St. Martin's, 1974. Crawford, C. The Art of Computer Game Design. Original publication 1982, book out of print. 15 Oct. 2000 <http://members.nbci.com/kalid/art/art.php>. Darley Andrew. Visual Digital Culture: Surface Play and Spectacle in New Media Genres. London: Routledge, 2000. Lunenfeld, P. Digital Dialectic: New Essays on New Media. Cambridge, Mass.: MIT P 1999. Mates, A. Effective Illusory Worlds: A Comparative Analysis of Interfaces in Contemporary Interactive Fiction. 1998. 15 Oct. 2000 <http://www.wwa.com/~mathes/stuff/writings>. Mastai, M. L. d'Orange. Illusion in Art, Trompe L'Oeil: A History of Pictorial Illusion. New York: Abaris, 1975. Miller, Robyn and Rand. "The Making of Myst." Myst. Cyan and Broderbund, 1993. Milman, M. Trompe-L'Oeil: The Illusion of Reality. New York: Skira Rizzoli, 1982. Murray, J. Hamlet on the Holodeck: The Future of Narrative in Cyberspace. New York: Simon and Schuster, 1997. Wertheim, M. The Pearly Gates of Cyberspace: A History of Cyberspace from Dante to the Internet. Sydney: Doubleday, 1999. Game References 7th Guest. Trilobyte, Inc., distributed by Virgin Games, 1993. Doom. Id Software, 1992. Excalibur. Chris Crawford, 1982. Myst. Cyan and Broderbund, 1993. Tomb Raider. Core Design and Eidos Interactive, 1996. The Crystal Key. Dreamcatcher Interactive, 1999. Citation reference for this article MLA style: Bernadette Flynn. "Towards an Aesthetics of Navigation -- Spatial Organisation in the Cosmology of the Adventure Game." M/C: A Journal of Media and Culture 3.5 (2000). [your date of access] <http://www.api-network.com/mc/0010/navigation.php>. Chicago style: Bernadette Flynn, "Towards an Aesthetics of Navigation -- Spatial Organisation in the Cosmology of the Adventure Game," M/C: A Journal of Media and Culture 3, no. 5 (2000), <http://www.api-network.com/mc/0010/navigation.php> ([your date of access]). APA style: Bernadette Flynn. (2000) Towards an aesthetics of navigation -- spatial organisation in the cosmology of the adventure game. M/C: A Journal of Media and Culture 3(5). <http://www.api-network.com/mc/0010/navigation.php> ([your date of access]).