Abstract: A first apparatus for displaying drawings comprises a housing having an aperture, a drawing sheet comprising electro-optic material movable through the aperture between closed and open positions, and a writing device for writing on the sheet as it moved between its closed and open positions. A second apparatus comprises a display member having a viewing surface, support means for supporting this display member above a floor, an electro-optic medium disposed on the display member, and a movable writing head for writing on the electro-optic medium. Another display comprises an optic medium with two display states visible through a viewing surface. A touch screen is disposed on the opposed side of the optic medium from the viewing surface, and the optic medium is deformable such that pressure applied to the viewing surface will be transmitted to the touch screen.

Abstract: An interferometric light modulating device having two viewing surfaces is provided. In some embodiments, the device can generate two distinct images, one on each side of the device, simultaneously.

Abstract: An electrophoretic display capable of improved contrast. A back substrate 52 provided with a transparent electrode 54 and a transparent substrate 53 provided with transparent electrodes 551 to 553 are arranged at a predetermined distance D. Between the transparent substrate 53 and the back substrate 52 are arranged a large number of microcapsules. In each of the microcapsules 56A is sealed a dispersion comprised of electrophoretic particles 57 dispersed in a dispersion medium 61 in advance by the microcapsulation technique. The plurality of microcapsules 56A are sandwiched between the transparent substrate 53 and the back substrate 52. The display surface side and the back side thereof are flat in shape.

Abstract: A MEMS optical display system includes an illumination source for providing illumination light, a collimating lens for receiving the illumination light and forming from it collimated illumination light, and a microlens array having an array of lenslets for receiving the illumination light from the collimating lens. The converging microlens array directs the illumination light through an array of pixel apertures in an aperture plate to a microelectrical mechanical reflector array positioned opposite the aperture plate. The microelectrical mechanical reflector array includes an array of microelectrical mechanical actuators that support reflectors in alignment with the array of pixel apertures and selectively orients the reflectors to direct the illumination light back through the pixel apertures (to form part of a display image) or against the aperture plate (to be blocked). The illumination light passing back through the pixel apertures passes through the microlens array and a beamsplitter to a display screen.

Abstract: The display system comprises a screen (1) made of an array of metal triangular facets (30) which are driven in and out by an array of pneumatic pistons (2) located behind the screen (1). The rear ends of the pistons (2) are flexibly connected by damped pivots (8) to a structural frame (7). The front ends of the pistons (2) are flexibly coupled to connection nodes between the facets (30) by connection devices (10) which have legs (13) which may splay apart as the pistons are pushed forwards. The pistons (2) may therefore be used to give the screen (1) of the facets (30) a visible 3-dimensional surface effect such as a sinusoidal deformation (101). The display system also includes an electronic control system for driving the pistons (2). The electronic control system may use a stored data file to produce a particular surface effect on the screen (1). Alternatively, the control system may respond in real-time to an input such as ambient sound, ambient lighting conditions or the like.

Abstract: A scanning display device is disclosed. The scanning display device includes: first to M-th scan mirrors (where M is an integer of at least 2), each of which scans a light signal in a first direction; and a scanning unit for scanning the light signal scanned by each of the first to M-th scan mirrors in a second direction, wherein a m-th scan mirror (where 1?m?M?1) scans the light signal in the first direction, and a n-th scan mirror (where 2?n?M) adjacent to the m-th scan mirror scans the light signal scanned by the m-th scan mirror in the first direction.

Abstract: Methods and apparatus are provided for preventing charge accumulation in microelectromechanical systems, especially in micromirror array devices having a plurality of micromirrors. Voltages are applied to the micromirrors for actuating the micromirrors. Polarities of the voltage differences between mirror plates and electrodes are inverted so as to prevent charge accumulation.

Abstract: There is provided a micromirror, which is provided with a reflection mirror, a first pair of torsion bars formed to protrude from the reflection mirror, a first supporting frame that supports the reflection mirror such that the reflection mirror is torsionally rotatable about a first rotation axis via the first pair of torsion bars, a second pair of torsion bars formed to protrude from the first supporting frame in a direction substantially perpendicular to a direction in which the first pair of torsion bars are extended, and a second supporting frame that supports the first supporting frame such that the first supporting frame is torsionally rotatable about a second rotation axis substantially perpendicular to the first rotation axis via the second pair of torsion bars. In this configuration, each of the second pair of torsion bars includes two separate conductive members.

Abstract: A pixel device, comprising; a first plate, a second plate disposed under the first plate, and a third plate disposed under the second plate; a first power supply for providing a first voltage to the first plate; a second power supply for providing a second voltage to the second plate; and a third power supply for providing a third voltage to the third plate.

Abstract: A digital display apparatus for a vehicle includes an optical engine that includes a light source, a reflection type digital light deflector that has a plurality of micro mirror elements, a light irradiation unit that irradiates reflected light from the reflection type digital light deflector on a road surface and the like, and an information display unit. The reflection type digital light deflector digitally switches over a direction of reflection of a light from the optical engine between an ON and an OFF state. The information display unit displays information using a contrast between the ON reflected light and an OFF reflected light from the reflection type digital light deflector on the road surface and the like through the light irradiation unit.

Abstract: An optical switching element having a simple configuration and high response and capable of performing gradation display by area gradation is provided. In a state where a light extracting portion is in contact with an upper substrate, light enters the light extracting portion from the upper substrate, emits from the back face of the light extracting portion, is passed through a lower substrate, and becomes transmission light. In a state where the light extracting portion is attracted by the lower substrate side, the incident light is totally reflected by a total reflection face, and total reflection light emits from a V-shaped groove. The incident light can be switched in two directions and obtained as the transmission light and the total reflection light.

Abstract: A spatial light modulator includes a first region and a second region. A light-absorbing layer contacts at least a portion of the second region. The light absorbing layer includes a first layer and a second layer, the second layer having a reflectivity less than about 75%.

Abstract: Electromechanical shutter and display comprising a two-dimensional matrix of such shutters are proposed, in which the membrane under the force of electrostatic attraction moves from its original position parallel to the substrate plane into a final position normal to the substrate plane, thereby transferring the shutter, or display pixel, from its “off” state into its “on” state. To produce the “on” state, the electrostatic force is applied only to a narrow conductive strip placed on the side of the membrane and rotates the membrane around the torsion hinges attached to this strip. Two-and three-electrode shutter and pixel configurations are considered. Both versions provide a bi-stable membrane behavior, which implies that the voltage needed to transfer the membrane into the “on” state is larger than the voltage needed to maintain the membrane in this state. This feature of bi-stability allows realization of functions “pixel hold” and “pixel select” using a simple passive matrix architecture.

Abstract: Due to an ever growing shortage of conventional energy sources, there is an increasingly intense interest in harnessing solar energy. The instant invention can contribute to the goal of achieving environmentally clean solar energy to be competitive with conventional energy sources. Method and apparatus are presented for coupling to a transparent sheet with an embedded array of preformed or formable mirrored micro-balls for use in a solar energy concentrator, and functionally similar applications such as optical switches and solar rocket assist. Mirrored micro-balls and particulate formable mirrors in cells are covered with a thin spherical shell of lubricating liquid so that they are free to rotate in an almost frictionless encapsulation in the sheet. Induced polarization electric or magnetic dipoles in the mirrors provide a method of controlling the alignment of the mirrored balls. Electrophoretically and magnetophoretically forming mirrors in situ on a rigid surface in a rotatable cell are also disclosed.

Abstract: A dynamic memory cell for storing data in a display having at least one MEMS device for each pixel has at least two dynamic memory elements per pixel, including first and second dynamic memory elements, each including at least one capacitor, both of the first and second memory elements being electrically coupled to the MEMS device of a single pixel. A sense amplifier is configured to amplify the data signal and to latch data in response to a differential data signal and a clock signal, self-refreshing the data and loading data to the MEMS device as required.

Abstract: This invention deals with the broad general concept for dynamic reflection, illumination and direct image projection. A mini-optics reflection and focussing system is presented that ranges from interior illumination, to exterior illumination, to large scale space based illumination, to ordinary and to telescopic image formation. It can be used both as a source of illumination, and to project images, figures, and the written word. This system has broad applications such as dynamic full color displays. Its use of a novel induced dipole coupling for rotation of planar mirrors lets it operate with greater simplicity and efficiency than other display devices. Furthermore in its capacity as a high altitude active reflector of solar radiation, it can be utilized to supply illumination, energy, and provide climate control.

Abstract: A display system (10) with reduced speckle has a light source (70) providing an illumination beam and a linear light modulator (85) having at least one linear array of light modulating devices for forming a modulated beam. The modulated beam has a plurality of orders of diffracted light. An obstructing element (82r,82g,82b) blocks a zeroeth order reflected light from the modulated beam. An angle-transforming optical assembly (30) anamorphically conditions the modulated beam. A scanning element (77) scans the modulated beam toward a display surface (90) for forming a two-dimensional image thereon.

Abstract: An image display apparatus comprising an image display device, a shield member, and a drive mechanism. The drive mechanism drives the shield member in synchronization with display of the image.

Abstract: A mirror assembly including an active lens and a reflective surface. The mirror assembly may change its refractive index when a voltage is applied to the active lens, thereby changing the field of view in the lens. Exemplary applications include a blind spot system in a motor vehicle, in which, upon sensing another vehicle in a driver's blind spot, the mirror assembly changes the driver's field of view to include the blind spot. Additional applications include a magnifying mirror for shaving or applying cosmetics.

Abstract: An optical switching element having a simple configuration and high response and capable of performing gradation display by area gradation is provided. In a state where a light extracting portion is in contact with an upper substrate, light enters the light extracting portion from the upper substrate, emits from the back face of the light extracting portion, is passed through a lower substrate, and becomes transmission light. In a state where the light extracting portion is attracted by the lower substrate side, the incident light is totally reflected by a total reflection face, and total reflection light emits from a V-shaped groove. The incident light can be switched in two directions and obtained as the transmission light and the total reflection light.

Abstract: The present invention relates to a moveable image display system comprising a plurality of moveable display frames, capable of displaying images, a power transmitter and a data transmitter. There are no electrical connections between the moveable display frames and the data or power sources, however the moveable display frames are mechanically and electrically connected to each other. The moveable display frames are capable of moving relative to each other and are capable of moving together relative to the data and power sources.

Abstract: A modulator for and a method of modulating an incident beam of light including means for supporting a plurality of active elements and a plurality of bias elements, each active and bias element including a light reflective planar surface with the light reflective planar surfaces of the plurality of active elements lying in a first parallel plane and the plurality of bias elements lying in a second parallel plane wherein the plurality of active and bias elements are parallel to each other and further wherein the plurality of bias elements are mechanically or electrically deflected with respect to the plurality of active elements. Each of the plurality of bias elements is deflected an odd multiple of the wavelength of an incident light wave divided by four and the plurality of light reflective planar surfaces of the plurality of active elements move between the first parallel plane to the second parallel plane.

Abstract: An electrophoretic display has a viewing surface, and includes an image pixel. The image pixel includes a first plurality of particles having a first mobility, and a second plurality of particles having a second mobility. At a first addressing voltage, the first mobility is greater than the second mobility. At a second addressing voltage, the second mobility is greater than the first mobility. At least one of the first and second mobilities is a variable function of voltage, i.e., a function of an applied electric field. Application of the first addressing voltage produces a first optical state, which is determined by a motion of the first plurality of particles. Application of the second addressing voltage produces a second optical state determined by a motion of the second plurality of particles.

Abstract: A wearable pixelated apparel video-displaying system is disclosed comprising at least one flexible lightweight pixelated material having a contiguous imaging surface comprised of a multitude of pixels capable of displaying typical video rate, video image content which is contiguous in appearance and which covers up to all of the surface. The apparatus is equipped to playback, control and display imagery according to the size and the shape of one or more pixelated material segments making up the video-displaying apparel. The apparatus has an input/output interface a digital media content playback device, a user interface means for a user to communicate with the apparatus and to control the playback of at least one source of video content. In one embodiment the pixelated-image displaying apparel is contiguously formed into a single garment. In a second embodiment a plurality of apparel segments are adjoined to one another by attachment, and are electronically coupled together.

Abstract: A first apparatus for displaying drawings comprises a housing having an aperture, a drawing sheet comprising electro-optic material movable through the aperture between closed and open positions, and a writing device for writing on the sheet as it moved between its closed and open positions. A second apparatus comprises a display member having a viewing surface, support means for supporting this display member above a floor, an electro-optic medium disposed on the display member, and a movable writing head for writing on the electro-optic medium. Another display comprise an optic medium with two display states visible through a viewing surface. A touch screen is disposed on the opposed side of the optic medium from the viewing surface, and the optic medium is deformable such that pressure applied to the viewing surface will be transmitted to the touch screen.

Abstract: A magnetic display has two non-magnetic substrates, at least one of which is transparent; and a microcapsule coating layer is applied between the non-magnetic substrates. The microcapsules contain and seal light-absorptive black magnetic fine particles and light-reflective non-magnetic fine particles dispersed in an oily dispersion liquid. An array layer is buried in a capsule wall of each of the microcapsules for enclosing the oily dispersion liquid that contains the light-absorptive black magnetic fine particles and light-reflective non-magnetic fine particles. The array layer includes flake-shaped particles with a multi-layered structure for converting the black color of a character or image formed on a display surface, which is a color inherently exhibited by the light-absorptive black magnetic fine particles, into a variety of interference colors.

Abstract: A drive controller for controlling to change the orientation of a display surface of a display in accordance with the seating position of occupants aboard a vehicle. A display unit is rotatably mounted on a vehicle. A controller automatically rotates the display unit to a first position where the display surface is oriented toward a driver seat, when an occupant is seated solely in the driver seat. The controller rotates the display unit to a third position where the display surface is oriented toward a front passenger seat, when an occupant is seated solely in the front passenger seat. The controller rotates the display unit to a second position where the display surface is oriented toward the middle point between the driver seat and the front passenger seat, on detecting both of the occupants are seated respectively in the driver seat and the front passenger seat.

Abstract: An optical interference reflective element has a light-incident electrode and a light-reflective electrode, and each or both of the two electrodes are made of a display part and a wiring part which are electrically connected to each other with a connection part. A plurality of the interference reflective elements are connected to form an electrode line by the wiring parts, and the electrode line is used in an optical interference reflective structure formed by the optical interference reflective elements that is operated in a passive matrix mode.

Abstract: An integrated driver for controlling operations of display systems having spatial light modulators that are operated in binary states is provided.

Abstract: An actuated film display device comprises a first fixed electrode, a first movable film electrode, which is placed to face the first fixed electrode to form a first optical path on an opposing side to the first fixed electrode, and which has a fixed end and a movable end, the movable end being displaced toward the first fixed electrode by application of a first potential difference between the first fixed electrode and the first movable film electrode, thereby shutting off the first optical path, a second fixed electrode placed at a predetermined distance from the first fixed electrode, and a second movable film electrode, which is placed to face the second fixed electrode to form a second optical path on an opposing side to the second fixed electrode, which has a fixed end and a movable end, the movable end being displaced toward the second fixed electrode by application of a second potential difference between the second fixed electrode and the second movable film electrode, thereby shutting off the second

Abstract: In one aspect, the invention includes a fader controller comprised of a longitudinally extending track having a portion thereof extending over an image area of an electronic display, and a fader cap joined to the track for longitudinal sliding translation therealong. A plurality of permanent magnets are spaced along the track, and the fader cap includes at least one electromagnet. Conductive rails extend longitudinally on the track, and the fader cap includes contacts that electrically engage the conductive rails. The electromagnets are actuated to translate the fader cap distally or proximally along the track. In another aspect, the invention provides a magnetic arrangement for removably joining one or more controller device to a flat panel electronic display, whereby controllers such as switches, knobs, and faders (slide controllers) may be superposed on the display.

Abstract: A lighting apparatus used for a projection type display is provided, which can change the incident ray volume to an optical modulation device without changing the optical output intensity of the lamp, and can exhibit excellent effects in expressive power of an image and adaptability to the use environment. The lighting apparatus of the present invention comprises; a light source, two fly-eye lenses constituting a uniform lighting device, and a shading plate arranged between these fly-eye lenses and constituting a dimming device for adjusting the amount of light of the outgoing light from the light source. The angle of inclination of the shading plate is controlled based on an image signal supplied to the optical modulation device, thereby enabling adjustment of the amount of light.

Abstract: The present invention provides a display device formed with an array of a plurality of pixels, which comprises: fixed elements with surfaces colored a first color, the fixed elements being arranged in correspondence with the pixels; movable elements with surfaces colored a second color, the movable elements being arranged in correspondence with the pixels; support elements supporting the movable elements at first ends thereof, the support elements being rotatable; and a inclined angle changing device configured to contact second ends of the support elements to change the inclined angle of the support elements; wherein, changing the inclined angles of the support elements allows the movable elements to move between rear surfaces of the fixed elements and adjacent front surfaces of the fixed elements.

Abstract: A spatial light modulator has: a support substrate that has an electrode layer; and a movable thin film that has at least an electrode layer, and that is opposingly placed above the support substrate with being separated by a predetermined gap distance in a manner that the movable thin film is flexurally deformable toward the support substrate, and in which a predetermined driving voltage is applied between the electrode layer of the support substrate and the electrode layer of the movable thin film to cause the movable thin film to be deflected toward the support substrate by an electrostatic force acting between the electrode layers. A returning electrode is disposed on an side of the movable thin film opposite to the side which is opposed to the support substrate to apply an electrostatic force of attracting the movable thin film when a driving voltage is applied.

Abstract: A crosspiece precursor and a picture element assembly precursor are hardened at mutually different timings to form a crosspiece and a picture element assembly. For example, the crosspiece precursor is firstly hardened to form the crosspiece. After that, the picture element assembly precursor is hardened while allowing an upper end surface of the picture element assembly precursor to make pressed contact with an optical waveguide plate, by displacing an actuator element toward an actuator substrate. The picture element assembly, which is formed by hardening the picture element assembly precursor, reliably abuts against the optical waveguide plate when a display device is in a light emission state.

Abstract: An optical switching element having a simple configuration and high response and capable of performing gradation display by area gradation is provided. In a state where a light extracting portion is in contact with an upper substrate, light enters the light extracting portion from the upper substrate, emits from the back face of the light extracting portion, is passed through a lower substrate, and becomes transmission light. In a state where the light extracting portion is attracted by the lower substrate side, the incident light is totally reflected by a total reflection face, and total reflection light emits from a V-shaped groove. The incident light can be switched in two directions and obtained as the transmission light and the total reflection light.

Abstract: The present invention comprises an electromagnetophoretic ink material for use as electronic and magnetic display elements. In particular, the present invention relates to the preparation and use of microencapsulated aspect elements having both an electrostatic layer and a magnetic layer, and that can be addressed to produce a display aspect by the application of external electric fields and external magnetic fields.

Abstract: A micromechanical panel display driver is shown in which only one driver and control bus are needed for each color. Furthermore, the elements are made with uniform film thicknesses, thereby minimizing the number of steps needed to fabricate the display. Here 6 bits are provided with temporal and aperture weighting. The use of temporal weighting generally requires the activation of most pixels twice/frame, which consumes considerable power. It should also be possible to eliminate temporal weighting by redistributing the contact area into a larger number of aperture weights and by adding a row electrode. Here pixels are activated only in response to a charge in the image. This generally reduces the drive power, since many pixels in a typical image do not change from frame to frame.

Abstract: A micro-mirror device for an image display apparatus which can change the travel path of incident light by pivoting a mirror, which corresponds to a pixel and can increase optical efficiency by pivoting the mirror in the direction of the sides of the mirror. The micro-mirror device for an image display apparatus includes a substrate, a landing pad provided on the substrate, and a pair of base electrodes provided on opposite sides of the landing pad. A pair of first posts protrude from the upper surface of the landing pad, and are isolated from each other by a predetermined interval. A girder, supported by the pair of first posts, pivots toward the sides of the base electrodes due to an electrostatic attraction. A second post protrudes from the upper surface of the girder. A mirror, which is supported by the second post, reflects incident light, and receives power via the landing pad.

Abstract: A pixel-based display utilizes persistence-of-vision to sweep text and graphics in a cylindrical plane, including time and date, custom messages and animations. The display is generated from a light array with a column of modulated light emitting elements, which is mounted on a rotating display assembly. Power and data are combined on a fixed control assembly and inductively coupled to the display assembly. A control assembly processor interprets a display application language that describes display-specific tasks to generate command, mode, character and graphic data for the display assembly. The control assembly processor also reads a trigger position sensor and adds a trigger delay to generate a virtual trigger command, which provides for flexible display positioning and scrolling display effects.

Abstract: The present invention comprises an electromagnetophoretic ink material for use as electronic and magnetic display elements. In particular, the present invention relates to the preparation and use of microencapsulated aspect elements having both an electrostatic layer and a magnetic layer, and that can be addressed to produce a display aspect by the application of external electric fields and external magnetic fields.

Abstract: A first electrode layer 12, a first piezoelectric film layer 13, a second electrode layer 14, a second piezoelectric film layer 15, and a third electrode layer 16 are layered in that order on a substrate 11; these are constrained so as not to expand or contract in a thickness direction and a piezoelectric transducer is constructed thereby.

Abstract: A light beam display employing interlaced light beam scanning comprising a display screen having a vertical and a horizontal dimension, a source of a plurality of light beams and an optical path including a movable reflector having a plurality of reflective facets between the display screen and the light beam source. The movable reflector directs the plural light beams to the display screen via one or more facets of the movable reflector to simultaneously illuminate plural different scan lines of the display which are spaced apart by plural non-illuminated scan lines. An optical mechanical element is provided for vertically shifting the light beams so as to illuminate different scan lines of the display screen.

Abstract: A wireless transmission network card frame kit assembly consists of: a lower frame for housing electric circuits or other necessary elements including a first section which is wedged in a computer socket when the network card is inserted in the computer socket, and a second section for housing wireless receiving or emitting modules being exposed outside the computer when the network card is inserted in the computer socket to facilitate wireless transmission; an upper frame having an assembly section located above the second section when assembled and faced the first section; an upper cap covering the first section of the lower frame and having an overlap section to overlap over the assembly section; and a lower cap to encase the bottom side of the first section of the lower frame and the overlap section of the upper frame, and engage tightly with the upper cap at indented grooves of the upper cap.

Abstract: An electrophoretic display comprising at least one in-plane gating electrode. The gating electrode(s) provide a gating effect, which raises the effective threshold voltage to prevent the undesired movement of the charged particles in the cells. The design of the invention can be manufactured using low cost materials by efficient processes.

Abstract: A reflective display device includes a transparent display panel into which light is introduced. A driving section is disposed at the back of the display panel. Actuator elements corresponding to a number of picture elements are arranged in the driving section. A picture element assembly is provided on each of the actuator elements. The picture element assembly includes a light-reflecting layer and a color filter. A light-absorptive material is filled between the display panel and an actuator substrate. The actuator elements are selectively driven according to an attribute of an input image signal for controlling displacement of the picture element assembly in a direction closer to or away from the display panel, thereby adjusting degree of light-absorption and/or light reflection between the display panel and the picture element assembly so that a screen image corresponding to the image signal is displayed on the display panel.

Abstract: An optical system of a display including a light conducting plate introduced with light and a panel portion provided to oppose to one plate surface of the light conducting plate. The panel portion includes a driving part arranged with actuator parts each corresponding to a plurality of pixels so as to control displacement motions of the actuator parts in the contacting and separating directions to and from the light conducting plate correspondingly to attributions of input image signals, thereby controlling leaked light-beams in predetermined regions of the light conducting plate, to thereby cause the light conducting plate to display an image corresponding to the input image.

Abstract: The present invention relates to methods and apparatus for addressing pixels in a display. More particularly, the present invention relates to methods and apparatus for addressing pixels in a display using one or more movable mechanical scanning mechanisms. The mechanical scanning mechanisms and one or more stationary addressing elements provide electrical field addressing for control of the desired pixel(s) in a display.

Abstract: In order to provide a device for generating an image on an image surface with N×M image elements which can be illuminated individually, comprising a plurality of semiconductor radiation sources, each of which generates radiation with at least one color, an optical imaging means with a beam guidance, by means of which a plurality of image elements can be illuminated with each of the semiconductor radiation sources, with which it is possible to generate an image on an image surface in as simple a manner as possible using radiation sources, it is suggested that the image surface (12) be divided into a plurality of continuous image surface sections (14), each comprising a two-dimensional ensemble of image elements (16), that an illumination unit (20, 220, 320) be associated with each of the image surface sections (14) and that each illumination unit (20, 220, 320) have at least one semiconductor radiation source (30) and at least one optical imaging means (40, 240, 340) of its own associated with this illum

Abstract: Apparatus including a substrate, having a substrate surface; an object having a maximum dimension smaller than 1 mm; an axle, having an axis, attached to the object body; and an axle support attached to the substrate and having a support surface. The axle has a rounded cross-section, as manufactured and forms a non-zero angle with a perpendicular to the surface. The object is capable of rotating about the axle.