A light deflector can be driven by a low voltage by reducing contact area with a plate shape member and other members. The light deflector can be driven by a low voltage by reducing a contact area with a plate shape member and other members. More particularly, a frictional force and fixing strength are reduced at a contact area with a control member deployed around a plate shape member and the plate shape member. The fixing strength is reduced at a contact area with a fulcrum member and the plate shape member. Also, the fixing strength is reduced at a contact area with a substrate (or an insulation layer on a substrate) and the plate shape member.

1. Field of the Invention
The present invention generally relates to light deflectors, light deflection arrays, image forming devices, and projection type image display apparatuses, whereby the direction of outgoing light compared to incident light is changed. For example, the present invention can be used for image forming devices such as electro-photographic type printers or copiers, or projection type image display apparatuses such as projectors or digital theater systems.
2. Description of the Background Art
As a type of light deflector, which moves or transforms a mirror using an electrostatic force, a torsion beam type digital micro mirror device (DMD) has been proposed by L. J. Hornbeck et al. The DMD is a device including a beam and a mirror with a hinge. The beam is twisted at the hinge by electrostatic force. The electrostatic force occurs as a result of different electric potentials applied between electrodes facing each other at a plane surface over an air space. As a result of this, the mirror surface is changed, and therefore light deflection is performed. In addition, the details of the DMD are described in "Proc. SPIE Vol. 1150, pp. 86-102, 1989".
In addition, as a product using the DMD, a projection type image display apparatus is described in "A MEMS-Based Projection Display Proceedings Of The IEEE, Vol. 86, No. 8, August 1998, page 1687 to page 1704". Another device, but in which the direction of outgoing light compared to incident light is not changed, is a light valve using a diffraction grating proposed by D. M. Bloom et al. as a typical light modulation apparatus (similar to a light inclination device in a meaning of performing on/off of light). A diffraction grating light valve (GLV) is disclosed in "Optics Letters, Vol. 7, No. 9, pp 688˜pp 690", Japanese Patent No. 2941952, Japanese Patent No. 3016871, and Japanese Patent No. 3164824. The GLV, as a device including plural elements, has plural long and narrow ribbons of two groups. The ribbons have a light reflection domain in an appearance. The ribbons of the two groups are changed in height by an electrostatic force to produce a potential difference with electrodes, which face the ribbons over an air space. As a result, diffraction of light occurs, a strength of reflection light varies, and light is modulated. In addition, a projection type image display apparatus with the use of GLV is described in Japanese Laid Open Patent Application No. 2002-131838.
The above-discussed background light deflectors include moving or transforming apparatuses like mirrors or ribbons, which have a fixed edge.
FIG. 1 is a view showing a background art light deflector. FIG. 1A is a top view of the light deflector. FIG. 1B is a B-B′ cross-sectional view of FIG. 1. In addition, a light deflector of FIG. 1 is illustrated showing only one light deflector in an array that is arranged in 2 dimensions.
The above described background light deflector is a type in which an incident light beam changes a reflection course in a light reflection area. The light deflector has a substrate 101, plural control members 102, a fulcrum member 103, a plate shape member 104, plural electrodes 105, and an insulation layer 106 (fulcrum member 103 and electrodes 105a to 105d are illustrated with transparency). The plural control members 102 have stoppers in upper parts respectively. The stoppers are provided at plural ends of substrate 101 respectively.
The fulcrum member 103 has a top end, and it is established in the upper side of substrate 101. The plate shape member 104 does not have a fixed edge. In addition, the plate shape member 104 has a light reflection area and a conductive material layer of a member having electroconductivity in at least one part. Plate shape member 104 is deployed to move in the space between insulation layer 106 and fulcrum member 103, but has its movement stopped by the stoppers. The plural electrodes 105 are formed on top of the substrate respectively. In addition, the plural electrodes 105 face a conductive material layer of plate shape member 104. Applying different electrical potentials to the electrodes 105 controls an inclination or slant of the plate shape member 104.
The above-described light deflector has the following advantages:    (a) Control of an inclination corner of a mirror (plate shape member 104) is easy and stable with a dip angle being determined by contact of a fulcrum member and a substrate and a plate shape member,    (b) Reply speed of inclining plate shape member of a film to turn fast at high speed by applying different electrical current potentials to the electrodes can be achieved,    (c) The plate shape member does not have a fixed edge, and thereby there is little long-term deterioration, and the plate shape member can be driven by a low voltage,    (d) There are few shocks by a collision with a stopper as the stopper is small, and a lightweight plate shape member can be formed by a semiconductor process, and there is a little long-term deterioration,    (e) The on/off ratio of reflection light (the S/N ratio in picture machinery, the contrast ratio in picture machinery) can be improved by the constitution of a control member and a plate shape member and its light reflection area,    (f) A miniaturization and an integration are possible at a low cost by employing a semiconductor process,    (g) A light deflection of 2 dimensions of 1 axis and a light deflection of 3 dimensions of 2 axes are possible by disposing plural electrodes.
FIG. 2 and FIG. 3 are examples of a drive method of the above described background light deflector disclosed in prior application Japanese Patent Application No. 2002-282858.
FIG. 2 shows the condition that a plate shape member is inclined by driving as an example with the light deflector of FIG. 1 to be slanted in the position as shown in FIG. 1. FIG. 2A is a cross-sectional view of A-A′ and C-C′ in a STEP 1. FIG. 2B is a cross-sectional view of A-A′ and C-C′ in a STEP 2. In FIG. 2, light deflection movement is performed by changing an electrical current potential applied to electrodes 105a, 105b, 105c, 105d. An occurring electrostatic force (shown by the black arrows) is illustrated by electrical current potential applied as shown in FIG. 2A and FIG. 2B to electrodes 105a to 105d.
FIG. 3 shows a timing chart of applying the electrical current potential to each electrode of FIG. 2. A drive method of a background light deflector and incline displacement movement of plate shape member 104 (in other words a light deflection operation) are explained in FIG. 2 and FIG. 3. At first, in STEP 1 of FIG. 3, high electrical current potential 'a' is applied to electrode 105a, low electrical current potential 'c' is applied to electrode 105b, and middle electrical current potential 'b' is applied to electrode 105c and electrode 105d. Then, the electrical current potential of the plate shape member 104, which has a conductive material layer facing electrode group 105 and that is floating electrically, becomes equal to middle electrical current potential 'b'. Therefore, an electrostatic force does not occur at electrodes 105c and 105d of the ON side, but an electrostatic force occurs at electrodes 105a and 105b of the OFF side as shown in FIG. 2A. As a result, plate shape member 104 slants upward toward the OFF side. This movement may be a reset movement to be made at the beginning of a light deflection movement in addition to being at STEP 1 a serial light deflection movement.
Subsequently, in STEP 2 of FIG. 3, high electrical current potential 'a' is applied to electrode 105c, low electrical current potential 'c' is applied to electrode 105d, and middle electrical current potential 'b' is applied to electrode 105a and electrode 105b. Then, the plate shape member 104 floating electrically becomes equal to electrical current potential 'b'. As a result, an electrostatic force does not occur at electrodes 105a, 105b at the OFF side, but an electrostatic force occurs as shown in FIG. 2B at electrodes 105c and 105d at the ON side. Then, the plate shape member 104 slants upward toward the ON side.
In addition, plate shape member 104 of the above described light deflector may be formed of a single layer in FIG. 1, but it may be preferable to form the plate shape member of plural layers. In addition, in FIG. 2, and the drive of FIG. 3, light deflection movement in an ON direction in 2 dimensions of 1 axis with an OFF direction is described, moving the plate shape member either toward the electrodes 105c, 105d side or electrodes 105a, 105b side. However, the electrodes 105a, 105c side and the electrodes 105b, 105d side the plate shape member 104 can be slanted by changing the voltage applied to electrodes 105a to 105d. In other words, a light deflection of 3 dimensions of 2 axes is possible, if the fulcrum member 103 is arranged as a cone in the center of a light deflector.
FIG. 4 is a view showing a further background art light deflector. In FIG. 4 the plate shape member 104 comes in direct contact with a fulcrum member 103, to constitute a light deflector when applying an electrical current potential to the plate shape member.
FIG. 4A is a top view of a light deflector (but fulcrum member 103 and electrodes 105a to 105d are illustrated with transparence). FIG. 4B is the cross-sectional view of B-B′. In addition, a light deflector described in FIG. 4 is one light deflector in an array that is arranged in 2 dimensions.
FIG. 4 shows a light deflector in which light rays incident on a light reflection area are changed by reflection, by inclining a member having a light reflection area being displaced with an electrostatic force, as in the light deflector of FIG. 1. The light deflector has a substrate 101, plural control members 102, fulcrum member 103, plate shape member 104, and plural electrodes 105. The plural control members 102 have stoppers in the upper parts respectively, and also the plural control members 102 are established in plural ends of substrate 101 respectively. The fulcrum member 103 has a top, and is formed in the upper side of substrate 101. The plate shape member 104 does not have a fixed edge. The plate shape member 104 has a light reflection area and a conductive material layer of at least one part of electroconductivity material. The plate shape member 104 is deployed to be mobile in a space between substrate 101 and fulcrum member 103, and to be stopped by the stoppers. The plural electrodes 105 are provided on top of the substrate respectively, and the plural electrodes 105 face a conductive material layer of the plate shape member 104.
A point of difference from the light deflector of FIG. 1 is in a contact point of a top of fulcrum member 103 contacting at least the back side of plate shape member 104, to have a member having electroconductivity and electrical current potential of plate shape member 104 in contact with fulcrum member 103.
One example of a driving method of the above described background light deflector is explained in FIG. 5 and FIG. 6. The driving method described in FIG. 5 and FIG. 6 is a background driving method. In the driving method an electrical current potential of plate shape member 104 is given by contact with fulcrum member 103.
FIG. 5 shows the condition that a plate shape member is slanted as shown in the light deflector of FIG. 4. FIG. 5A is the cross-sectional view of A-A′ and C-C′ at STEP 1. FIG. 5B is the cross-sectional view of A-A′ and C-C′ at STEP 2.
In FIG. 5, light deflection movement is realized by changing an electrical current potential applied to electrodes 105a to 105d and electrical current potential applied to fulcrum member 103. In addition, an occurring electrostatic force (shown by the black arrows) is illustrated in FIG. 5A and FIG. 5B applied to electrodes 105a to 105d by an applied electrical current potential.
FIG. 6 shows a timing chart of applying an electrical current potential to each electrode of FIG. 5. A drive method of a background light deflector and incline displacement movement of plate shape member 104 (in other words a light deflection operation) are explained in FIG. 5 and FIG. 6.
At first, in STEP 1 of FIG. 6, high electrical current potential X is applied to electrodes 105a and 105b, 0V (the ground electrical current potential) is applied to electrodes 105c and 105d, and the ground electrical current potential is applied to the fulcrum member 103. The fulcrum member 103 includes a laminating with an electroconductivity member or an electroconductivity member, as a structure to which an electrical current potential is applied. The plate shape member 104 coming in contact with the fulcrum member 103 by application of the above-noted electrical current potentials becomes equal with the ground electrical current potential. By it, an electrostatic force does not occur at the electrodes 105c and 105d of the ON side, but occur at the electrodes 105a and 105b of the OFF side, as shown in FIG. 5A. Therefore, plate shape member 104 slants upward toward the OFF side, and is displaced.
In STEP 2 of FIG. 6, high electrical current potential X is applied to the electrodes 105c and 105d, the ground electrical current potential is applied to the electrodes 105c and 105d, and the ground electrical current potential is applied to the fulcrum member 103 continuously. Then, an electrostatic force does not cause the plate shape member 104 to come in contact with the fulcrum member 103 as against electrodes 105a of the OFF side, 105b reaching the ground electrical current potential because it is equal. An electrostatic force occurs as in FIG. 5B at electrodes 105c and 105d of the ON side. Therefore, plate shape member 104 slants upward toward the ON side, and is displaced.
In addition, plate shape member 104 of the above described light deflector can be formed of a single layer in FIG. 4, but may also be formed of plural layers. And also, FIG. 5 and FIG. 6 describe light deflection movement in 2 dimensions of 1 axis to slant toward the electrodes 105c, 105d in the OFF direction and the electrodes 105a, 105b in the ON direction. However, by changing the voltage applied to electrodes 105a to 105d, the plate shape member can be slanted toward the electrodes 105a, 105c in the OFF direction and the electrodes 105b, 105d in the ON direction. In other words, a light deflection of 3 dimensions of 2 axes is possible, if the fulcrum member 103 is arranged as a cone in the center of the light deflector.
In addition, the plate shape member described in FIG. 4, FIG. 5, and FIG. 6 is given electrical current potential via the fulcrum member 103 having electroconductivity, and there is no insulation layer 106 on the fulcrum member 103. Therefore, an electrode must be disposed so that plate shape member 104 does not come in contact with electrodes 105a to 105d on the occasion of slant displacement, as no insulation layer 106 is deployed on the top of electrodes 105a to 105d either.
FIG. 7 is a view of a production process of the light deflector described in FIG. 1. FIG. 7A to 7I are cross-sectional views of B-B′ in FIG. 1.
In the production process of FIG. 7A, the fulcrum member 103 is produced to a desired shape. At first a silicon oxidation layer composing fulcrum member 103 is formed on top of substrate 101 by a plasma CVD method using a phototype process method with the use of a photomask having a cardinality gradation property or a phototype process method to make transform heat after the regist pattern formation. Then the fulcrum member 103 is formed afterwards by a dry etching method. Alternatively, a silicon oxidation layer composing fulcrum member 103 can be formed on silicon substrate 101.
FIG. 7B is a view of a production process of the electrodes 105a, 105b, 105c, and 105d described in FIG. 1. Electrodes 105a to 105d are formed with a film of a nitride titanium (TiN) layer. A TiN film layer is made using Ti targeted DC magnetron sputtering method, and is then patternized as electrodes 105a to 105d of a plural number by a phototype process method and dry etching.
FIG. 7C is a view of a production process of the insulating layer 106 on electrodes 105a to 105d, which is a silicon oxidation layer formed by a plasma CVD method on the electrodes 105a to 105d.
FIG. 7D is a view of a production process of a first sacrificial layer 401. A silicon layer which is an amorphous substance, is formed by a sputtering method. A planarization is then executed by processing time control by CMP technology. It is important that a film thickness of an amorphous substance silicon layer left on the top top of fulcrum member 103 is controlled. A remaining amorphous substance silicon layer is the first sacrificial layer 401. In addition, as the sacrificial layer, a polyimide layer or photosensitivity organic layer (a resist layer used generally in a semiconductor process) or plural crystallization silicon layers can be used additionally. And also, as a technique of a planarization, a re-flow method and background method by heat-treatment by dry etching can be used.
FIG. 7E is a view of a production process of the plate shape member. The plate shape member has a high light reflection. The plate shape member is made of an aluminum layer accumulated by sputtering to form conductive material layer 104, which is patternized by a phototype process method and dry etching afterwards.
FIG. 7F is a view of a production process of a second sacrificial layer 402. The second sacrificial layer 402 is made of a silicon layer that is an amorphous substance by a sputtering method. In addition, a polyimide layer or photosensitivity organic layer (a resist layer used generally in a semiconductor process) or plural crystallization silicon layers can be used additionally as the sacrificial layer.
FIG. 7G is a view of a production process of the control member 102 having circumferential stoppers that separate individually the light deflector plate shape member 104. By a phototype process method and dry etching, the first sacrificial layer 401 and the second sacrificial layer 402 are compared with plate shape member 104 simultaneously, and are at least somewhat patternized.
FIG. 7H is also a view of a production process of arranging the stoppers around the control member 102. A silicon oxidation layer composing control member 102 having a stopper is formed by a plasma CVD method. By a phototype process method and dry etching, a silicon oxidation layer is patternized afterwards at arbitrary points. In addition, control member 102 having a stopper is not confined to the arrangement shown in FIG. 1. It is preferable that control member 102 is positioned leaving an air space above plate shape member.
FIG. 7I is a view of a production process to be completed for a light deflector. An etching removes the remaining first sacrificial layer 401 and the second sacrificial layer 402 by a wet etching method through an aperture part, to provide a mobile range disposed above plate shape member 104 in an air space. A light deflector is completed therefore. The etching is not limited to wet etching, and sacrificial layer etching can be carried out by dry etching depending on a kind of the sacrificial layer. In addition, as for the sacrificial layer etching, selecting the etching materials is important, as is optimizing materials of plate shape member 104, to make the etching proceed in a substrate planar orientation.
As for the advantages of the above described light deflector, the plate shape member 104 contributing to a light deflection does not have a fixed edge. Therefore, light deflection movement is not accompanied with transformation displacement of a plate shape member (in other words it is exhausted, and it is transformed, and it is twisted, and it is transformed). However, the structure has problems, too. A plate shape member not having a fixed edge moves in an air space limited with a control member. As a result the following problems occur.
FIG. 8 and FIG. 9 are views showing the details of control member 102 at the point D of a light deflector of FIG. 1, and plate shape member 104. FIG. 8 shows the good case that plate shape member 104 does not come in contact with control member 102 having a stopper. FIG. 9 shows a bad case that the plate shape member 104 not having a fixed edge is moved, and completely touches a corner part of control member 102. FIG. 8A and FIG. 9A are top views. FIG. 8B and FIG. 9B are slant views. FIG. 8C and FIG. 9C are cross-sectional views of E-E′.
In FIG. 8 and FIG. 9, 102a is a stopper composed in the upper part of control member 102, and 102b is a support member independently supporting control member 102. In the ideal case described in FIG. 8, friction to prevent movement does not act on the plate shape member 104 as it is displaced around the fulcrum member 103, because plate shape member 104 does not contact support 102b.
On the other hand, in the case the plate shape member 104 shown in FIG. 9 completely comes in contact with control member 102 in a corner part, a frictional force acts on a movement against displacement of plate shape member 104 as it comes in contact with support member 102b of control member 102 (the white arrow in FIG. 9C). As the size of the control member 102 in a light deflector is comparatively small, when a driving voltage is comparatively high, about several tens of volts, the counter-force of friction does not have a great influence. However, when a driving voltage is comparatively low, about several volts to several tens of volts, there is a possibility of a false operation because of the counter-force of friction, and then a normal slant displacement of plate shape member 104 may not be generated. Paradoxically, an increase in a driving voltage reduces the influence of the frictional force.
The following description is another problem that may occur in plate shape member 104 that does not have a fixed edge with reference to FIG. 10. FIG. 10 is a view of the details of control member 102 shown in the point D of FIG. 1. In the state that a voltage is not applied to electrodes 105a to 105d (initial state), a condition arises in stopper 102a that plate shape member 104 is deployed against the control member 102 upper part.
The plate shape member 104 can move anywhere freely because it is not fixed. When the plate shape member 104 is furthest from electrodes 105a to 105d, the position of the plate shape member 104 becomes as shown in FIG. 10. FIG. 10A is a slant view, and FIG. 10B is a cross-sectional view of E-E′. In FIG. 10, because the plate shape member 104 contacts stopper 102a at a surface, the fixing strength, which is dependent upon surface energy of a layer to contact, begins to act. Then, in an early reset movement shown in FIG. 2A, the voltage to be applied to electrodes 105a to 105d increases to add an electrostatic force to overcome a fixing strength.
As above described, there are drawbacks in the background light deflector making a driving voltage increase by the plate shape member coming in contact with the control member and to overcome the fixing strength.
FIG. 11 is a view of another background light deflector. Problems of this light deflector will be described as follows. FIG. 11A is a top view of a light deflector (but fulcrum member 103 and electrode 105a to 105d are illustrated with transparence). FIG. 11B is a cross-sectional view of B-B′. In addition, a light deflector described in FIG. 11 shows only one light deflector of an array arranged in 2 dimensions. The light deflector described in FIG. 11 shows a constitution approximately similar to the light deflector described in FIG. 1. The point of difference is that the light deflector described in FIG. 11 is a light deflector that can move in only 2 dimensions on 1 axis. Therefore, the fulcrum member 103 is a point having a ridge shape of a length approximately the same as a plate shape member in a light deflection axis direction.
False movement of a light deflection outside a target direction can be restrained by composing fulcrum member 103 to have a ridge shape of a long span. However, there is the following problem by composing fulcrum member 103 to have a ridge shape of a long span.
FIG. 12 is a view of the details of the fulcrum member 103 and the plate shape member 104 of the light deflector described in FIG. 11. FIG. 12A is a top view. FIG. 12B is a cross-sectional view of G-G′. FIG. 12C is a cross-sectional view of H-H′. In FIG. 12, because the plate shape member 104 comes in contact with the fulcrum member 103 along a line, a fixing strength (as shown by the white arrows in FIG. 12C) from surface energy of a layer touching at a contact part arises. Such a fixing strength becomes an obstacle to incline displacement of plate shape member 104. Thereby, an electrostatic force to overcome the fixing strength has to be added. As thus described, a background light deflector has a drawback to make a driving voltage increase by coming in contact with a fulcrum member and to overcome a fixing strength.
Another problem is explained in the light deflector of FIG. 11. FIG. 13 shows the details of fulcrum member 103 and plate shape member 104 and electrodes 105 and insulation layer 106 of the light deflector described in FIG. 11. FIG. 13A is a top view. FIG. 13B is a cross-sectional view on G-G′. FIG. 13C is a cross-sectional view on I-I′.
In FIG. 13, because the plate shape member 104 comes in contact with the insulation layer 106 along a line, the fixing strength (as shown by the white space arrows in FIG. 13C) from surface energy of layers touching in a contact part arises. Such a fixing strength becomes an obstacle to incline displacement of plate shape member 104. Thereby, an electrostatic force to overcome the fixing strength has to be added. As thus described, a background light deflector has a drawback to make a driving voltage increase by coming in contact with a fulcrum member. As thus described, a background light deflector has a further drawback to make a driving voltage increase by coming in contact with the substrate or the insulation layer on a substrate.
The above described background light deflectors has such drawbacks.

Light deflector, light deflection array, image forming apparatus, and image projection display apparatus


Device for adjustable fixing of an accessory on a board for gliding comprising a base, comprising locations for fixing the accessory and receiving a bar having a toothed part capable of a positioning in a complementary toothed part integral with the board for gliding, wherein the bar is mounted so as to be movable in rotation on the base about an axis, comprises, on either side of this axis, the toothed part and an end, and which comprises a knob capable of occupying two different positions, comprising a cam surface that interacts with the end of the bar such that a first position of the knob corresponds to a low position of the toothed part and a second position corresponds to a high position of the toothed part.

Various devices are known that allow adjustment of the longitudinal position of a front stop of a ski-boot binding device with a view to adapting the binding to various boot lengths. A common prior-art solution is based on guide rails positioned on the ski, that include a toothed part on which a complementary toothed part integral with the front stop of the ski binding is positioned. When these toothed parts are released, the stop can be adjusted by being slid longitudinally along the guide rails. However, existing solutions all have drawbacks, including:                they require a tool for releasing the toothed parts. This tool has to be inserted via an opening and held in position during adjustment. In this case, solutions are not user-friendly and are impractical for rapid adjustment operations under any conditions such as, for example, on a ski trail, where the required specific tool is not always available; and/or        there is play present at the join between the two toothed parts, even in the configuration envisaged for skiing, which greatly diminishes control over guiding the ski; and/or        they are not fail-safe, i.e. they can give rise to accidental changes in setting during their use, which is dangerous because it may cause the skier to fall; and/or        they are complicated because they are based either on a large number of elements or on elements that are complicated to manufacture or to assemble; and/or        lastly, they are sometimes unattractive in appearance because unattractive mechanical elements can be seen.

Adjustable device for an accessory such as a front stop of a ski binding


A novel framework for fast and continuous registration between two imaging modalities is disclosed. The approach makes it possible to completely determine the rigid transformation between multiple sources at real-time or near real-time frame-rates in order to localize the cameras and register the two sources. A disclosed example includes computing or capturing a set of reference images within a known environment, complete with corresponding depth maps and image gradients. The collection of these images and depth maps constitutes the reference source. The second source is a real-time or near-real time source which may include a live video feed. Given one frame from this video feed, and starting from an initial guess of viewpoint, the real-time video frame is warped to the nearest viewing site of the reference source. An image difference is computed between the warped video frame and the reference image. The viewpoint is updated via a Gauss-Newton parameter update and certain of the steps are repeated for each frame until the viewpoint converges or the next video frame becomes available. The final viewpoint gives an estimate of the relative rotation and translation between the camera at that particular video frame and the reference source. The invention has far-reaching applications, particularly in the field of assisted endoscopy, including bronchoscopy and colonoscopy. Other applications include aerial and ground-based navigation.

Registration and alignment of images taken by cameras at different spatial locations and orientations within the same environment is a task which is vital to many applications in computer vision and medical imaging. For example, registration between images taken by a mobile camera and those from a fixed surveillance camera can assist in robot navigation. Other applications include the ability to construct image mosaics and panoramas, high dynamic range images, or super-resolution images, or the fusion of information between the two sources.
However, because the structure of a scene is inherently lost by the 2D imaging of a 3D scene, only partial registration information can typically be recovered. In many applications, depth maps can be generated or estimated to accompany the images in order to reintroduce the structure to the registration problem.
Most currently available 2D alignment algorithms use a gradient descent approach which relies on three things: a parameterization of the spatial relationship between two images (e.g., the 2D rotation and translation between two 2D images), the ability to visualize these images under any value of the parameters (e.g., viewing a 2D reference image rotated by 30 degrees), and a cost function with associated image gradient information which allows an estimate of the parameter updates to be calculated. Among the most straightforward and earliest of these algorithms is the Lucas-Kanade algorithm, which casts image alignment as a Gauss-Newton minimization problem [5]. A subsequent refinement to this algorithm includes the inverse compositional alignment algorithm which greatly speeds the computation of the parameter update by recasting the problem, allowing all gradient and Hessian information to be calculated one time instead of every iteration [6]. Several other improvements have centered around the choice of parameters and the corresponding image warps these parameterizations induce. For example, images obtained from two identical cameras observing the same scene from a different location can be approximately related by an affine transformation or an 8-parameter homography [7].
The main problem with these types of parameterizations is that they do not truly capture the physically relevant parameters of the system, and, in the case of the homography, can lead to overfitting of the image. A more recent choice of parameters attempts to match two images obtained from a camera that can have arbitrary 3D rotations around its focal point [8]. This algorithm succeeds in extracting the physically relevant parameters (rotation angles about the focal point). However, while it is able to handle small translations, it cannot handle general translation and treats it as a source of error.
Little has been done to tackle the problem of registration of two images generated by cameras related by a general rigid transformation (i.e., 3D rotation and translation). The main reason for this is that the accurate visualization of a reference image as seen from a different camera location ideally requires that the depth map associated with that image be known—something which is not generally true. In certain situations, such as a robot operating in a known man-made environment, or during bronchoscopy where 3D scans are typically performed before the procedure, this information is known. Indeed, even in situations where the depth map is unknown, it can often be estimated from the images themselves.
An example of this is the aforementioned shape-from-shading problem in bronchoscopy guidance [9]. Current practice requires a physician to guide a bronchoscope from the trachea to some predetermined location in the airway tree with little more than a 3D mental image of the airway structure, which must be constructed based on the physician's interpretation of a set of computed tomography (CT) films. This complex task can often result in the physician getting lost within the airway during navigation [1]. Such navigation errors result in missed diagnoses, or cause undue stress to the patient as the physician may take multiple biopsies at incorrect locations, or the physician may need to spend extra time returning to known locations in order to reorient themselves.
In order to alleviate this problem and increase the success rate of bronchoscopic biopsy, thereby improving patient care, some method of locating the camera within the airway tree must be employed. Fluoroscopy can provide intraoperative views which can help determine the location of the endoscope. However, as the images created are 2D projections of the 3D airways, they can only give limited information of the endoscope position. Additionally, fluoroscopy is not always available and comes with the added cost of an increased radiation dose to the patient.
A few techniques also exist that determine the bronchoscope's location by attempting to match the bronchoscope's video to the preoperative CT data. One method uses shape-from-shading, as in [2], to estimate 3D surfaces from the bronchoscope images in order to do 3D-to-3D alignment of the CT airway surface. This method requires many assumptions to be made regarding the lighting model and the airway surface properties and results in large surface errors when these assumptions are violated. A second method of doing this is by iteratively rendering virtual images from the CT data and attempting to match these to the real bronchoscopic video using mutual information [3] or image difference [4].
While these methods can register the video to the CT with varying degrees of success, all operate very slowly and only involve single-frame registration—none of them are fast enough to provide continuous registration between the real video and the CT volume. They rely on optimization methods which make no use of either the gradient information nor the known depth of the CT-derived images, and thus require very computationally intensive searches of a parameter space.

This patent is subject to a terminal disclaimer.

Fast 3D-2D image registration system with application to continuously guided endoscopy


A parallel reality game has a virtual world that parallels at least a portion of the real world. A captured region is identified within the virtual world that is associated with a team within the parallel reality game. A geographic region is identified within the real world corresponding to the captured region within the virtual world. Data associated with population density for at least a portion of the geographic region is accessed. A score is assigned for the captured region based on the population density.

Computer-based and/or electronic gaming systems are known that provide a shared virtual environment for many players to interact in a virtual world. With increased availability and connectivity to the Internet, many players from all over the world can interact in the virtual environment and perform various game objectives. However, such gaming systems typically do not include a virtual world that parallels the real world and that acts as a virtual game environment in which many players can interact and perform various game objectives in the parallel virtual world by navigating and performing actions in the real world.
A parallel reality game providing a shared virtual world that parallels at least a portion of the real world allows players to interact in the virtual world by navigating the real world. However, without game rules associated with regulating and/or scoring player interactions within the virtual world, the overall game experience may be significantly impacted.

Regulating and scoring player interactions within a virtual world associated with a location-based parallel reality game


Methods and systems are provided for recording time offset for video recording devices and services including receiving a request to record a program, wherein the program is associated with show schedule information including a start time and a channel identifier, determining that the channel identifier is associated with at least one offset value, calculating an offset start time based at least in part on the start time and the offset value, and storing a scheduled record time for the program using the offset value.

Developments in time shifting recording and playback technology such as the digital video recorder (DVR), have greatly reduced the complexity of recording shows for later viewing when compared to use of the VCR to record a television program onto a video cassette. Thanks to network connectivity to such things such as system clocks at the service provider, there is a good chance that we are past the days of an entertainment system component constantly flashing high noon "12:00" indefinitely.
While it is possible that we are beyond the aforementioned high noon situation, that is not to say that system clock times are always in sync. For example, if there is a disagreement between the system clock time of a service provider and the system clock of a content provider, part of a recorded show could be cut off. Thus, shortcomings still exist with current systems and there are heretofore unaddressed needs with previous solutions.

Systems and methods of recording time offset for video recording devices and services


Disclosed is a method of forming a resist pattern, including: applying a positive resist composition on a support 1 to form a first resist film 2; selectively exposing the first resist film 2 through a first mask pattern, and developing it to form a first resist pattern 3; applying a negative resist composition including an organic solvent (S″) containing an alcohol-based organic solvent on the support 1 that the first resist pattern 3 is formed, thereby forming a second resist film 6; and selectively exposing the second resist film 6 through a second mask pattern, and developing it to form a resist pattern denser than the first resist pattern 3.

The technology (pattern formation technology) of forming a fine pattern on a substrate and performing etching using the formed pattern as a mask, thereby processing a lower layer of the pattern, is adopted for producing an integrated circuit (IC) and the like in the semiconductor industry, and thus it has received great attention.
These types of fine patterns are formed from an organic material, and are formed, for example, using a lithography method, a nanoimprint method or the like. For example, lithography techniques include processes in which, for example, a resist film formed from a resist composition containing a base component such as a resin is formed on a support such as a substrate, the resist film is selectively exposed with irradiation such as light, an electron beam or the like through a mask (mask pattern) in which a predetermined pattern has been formed, and then a developing treatment is conducted, thereby forming a resist pattern of the prescribed shape in the resist film. A resist composition in which the exposed portions change to become soluble in a developing liquid is termed a positive resist composition, whereas a resist composition in which the exposed portions change to become insoluble in the developing liquid is termed a negative resist composition.
Then, the substrate is processed by etching using this resist pattern as a mask, thereby producing a semiconductor element or the like.
In recent years, advances in lithography techniques have led to rapid progress in the field of miniaturization. Typically, these miniaturization techniques involve shortening the wavelength of the exposure light source. Conventionally, ultraviolet radiation typified by g-line and i-line radiation has been used, but nowadays KrF excimer lasers and ArF excimer lasers are starting to be introduced in mass production. For example, by a lithography technique using ArF excimer lasers, a pattern formation with 45 nm-level resolution is now possible. Also, in order to further improve the resolution, research is also being conducted into lithography techniques that use F2 excimer lasers, electron beams (EB), extreme ultraviolet radiation (EUV) and X-rays, which have a shorter wavelength than the ArF excimer lasers and the KrF excimer lasers.
Resist compositions are required to have lithography properties such as high sensitivity to the aforementioned light source and enough resolution to reproduce patterns with very fine dimensions. As a resist composition which meets such requirements, there is used a chemically-amplified resist composition including a base component which exhibits changed solubility in an alkali developing solution under action of an acid, and an acid generator which generates an acid upon exposure (for example, see Patent Document 1). For example, a chemically-amplified positive resist typically includes, as a base component, a resin which exhibits increased solubility in an alkali developing solution under the action of an acid. When an acid is generated from the acid generator upon exposure in the formation of a resist pattern, the exposed portions are converted to an alkali-soluble state.
As a technique for further improving the resolution, a lithography method called liquid immersion lithography (hereinafter, frequently referred to as "immersion exposure") is known in which exposure (immersion exposure) is conducted in a state where the region between the objective lens of an exposure apparatus and the resist layer formed on a wafer is filled with a solvent (an immersion medium) that has a larger refractive index than the refractive index of air (see for example, Non-Patent Document 1).
According to this type of immersion exposure, it is considered that such high resolution as in the case of using a shorter wavelength light source or a larger NA lens can be attained by using an exposure light source with the same wavelength as used conventionally, without lowering of the depth of focus. Furthermore, immersion exposure can be conducted using a conventional exposure apparatus. As a result, it is expected that immersion exposure will enable the formation of resist patterns of higher resolution and superior depth of focus at lower costs. Accordingly, in the production of semiconductor devices, which requires enormous capital investment, immersion exposure is attracting considerable attention as a method that offers significant potential in the semiconductor industry, both in terms of cost and in terms of lithography properties such as resolution.
Immersion lithography is effective in forming patterns having various shapes. Further, immersion exposure is expected to be capable of being used in combination with currently studied super-resolution techniques, such as a phase shift method and a modified illumination method. Currently, as the immersion exposure technique, a technique using an ArF excimer laser as an exposure source is being actively studied, and water is mainly used as the immersion medium.
As a lithography technology which has been newly-proposed recently, there is a double patterning method in which a resist pattern is formed by conducting patterning more than once (see Non-Patent Documents 2 and 3).
According to the double patterning method, for example, it is considered that a first resist pattern is formed on a support using a first resist composition, and subsequently patterning is conducted using a second resist composition on the support that the first resist pattern is formed, therefore a resist pattern with higher resolution than the resist pattern formed through a single patterning can be formed.
[Patent Document 1] Japanese Unexamined Patent Application, First Publication No, 2003-241385.
[Non-Patent Document 1] Proceedings of SPIE, Vol. 5754, pp. 119-128 (2005).
[Non-Patent Document 2] Proceedings of SPIE, Vol. 5256, pp. 985-994 (2003).
[Non-Patent Document 3] Proceedings of SPIE, Vol. 6153, pp. 615301-1 to 19 (2006).


Some embodiments of the present invention generally relate to pillow devices comprising a pair of opposing lobe cushions connected by a cross member comprising a neck supporting cushion. In some embodiments the cushions may define a region for receiving a back portion of a human head in a cradling relation. Furthermore, according to some embodiments the cradle region can optionally be adjustable by the user.

A. Field of Invention
This invention generally relates to pillow devices for use by humans. The present invention also generally relates to methods for making and using such pillow devices.
B. Description of the Related Art
It is well known in the art to use cushions to support a person's head. One such cushion is an ordinary rectangular pillow. Such pillows work fine when the user is in a lying or reclined posture. However, the rectangular pillow does not readily remain in place when the user is in a seated or otherwise upright posture. More specifically, rectangular pillows lack any sort of structure that is adapted to mate with the head and shoulders of the user in a generally fixed relation to prevent movement. Although ordinary pillows can generally be shaped by the user by redistributing the stuffing material, they lack any fixed mating structure and therefore can readily lose their desired shape and shift. Some attempts to address this deficiency have included shaped pillows that fit around the neck. While this can be effective in supporting the head by limiting the lateral range of motion of the neck, this design can still allow the head to shift from side to side to an undesirable degree.
Accordingly, there is a gap in the art where no structure is provided to support the head by cradling the back of the head with a shaped pillow, thereby limiting the lateral range of motion of the neck.


In one exemplary embodiment, an automated medication preparation system according to the present invention includes automated preparation of a dosage of medication in a drug delivery devices, such as a syringe, and includes an automated transport device for controllably delivering each drug delivery device from one location to another location and a receiving member that is associated with the automated transport device and includes at least two pockets for receiving and retaining at least two differently sized drug delivery devices according to a predetermined orientation. The system also includes a controller in communication with the automated transport device for moving the automated transport device in an indexed manner.

Drug delivery devices are used in a number of different applications and settings. One type of drug delivery device that is commonly used in a medical or pharmaceutical setting is a disposable syringe. Disposable syringes are in widespread use for a number of different types of applications. For example, syringes are used not only to withdraw a fluid (e.g., blood) from a patient but also to administer a medication to a patient. In the latter, a cap or the like is removed from the syringe and a unit dose of the medication is carefully measured and then injected or otherwise disposed within the syringe.
As technology advances, more and more sophisticated, automated systems are being developed for preparing and delivering medications by integrating a number of different stations, with one or more specific tasks being performed at each station. For example, one type of exemplary automated system operates as a syringe filling apparatus that receives user inputted information, such as the type of medication, the volume of the medication and any mixing instructions, etc. The system then uses this inputted information to disperse the correct medication into the syringe up to the inputted volume.
In some instances, the medication that is to be delivered to the patient includes more than one pharmaceutical substance. For example, the medication can be a mixture of several components, such as several pharmaceutical substances.
By automating the medication preparation process, increased production and efficiency are achieved. This results in reduced production costs and also permits the system to operate over any time period of a given day with only limited operator intervention for manual inspection to ensure proper operation is being achieved. Such a system finds particular utility in settings, such as large hospitals, including a large number of doses of medications that must be prepared daily. Traditionally, these doses have been prepared manually in what is an exacting but tedious responsibility for a highly skilled staff. In order to be valuable, automated systems must maintain the exacting standards set by medical regulatory organizations, while at the same time simplifying the overall process and reducing the time necessary for preparing the medications.
Because syringes are used often as the carrier means for transporting and delivering the medication to the patient, it is advantageous for these automated systems to be tailored to accept syringes. However, the previous methods of dispersing the medication from the vial and into the syringe were very time consuming and labor intensive. More specifically, medications and the like are typically stored in a vial that is sealed with a safety cap or the like. In conventional medication preparation, a trained person retrieves the correct vial from a storage cabinet or the like, confirms the contents and then removes the safety cap manually. This is typically done by simply popping the safety cap off with one's hands. Once the safety cap is removed, the trained person inspects the integrity of the membrane and cleans the membrane. An instrument, e.g., a needle, is then used to pierce the membrane and withdraw the medication contained in the vial. The withdrawn medication is then placed into a syringe to permit subsequent administration of the medication from the syringe.
Typically, a drug is provided off the shelf in solid form within an injectable drug vial that is initially stored in a drug cabinet or the like. To prepare an injectable unit dose of medication, a prescribed amount of diluent (water or some other liquid) is added to the vial to cause the solid drug to go completely into solution. Mixing and agitation of the vial contents is usually required. This can be a time consuming and labor intensive operation since first it must be determined how much diluent to add to achieve the desired concentration of medication and then this precise amount needs to be added and then the vial contents need to be mixed for a predetermined time period to ensure that all of the solid goes into solution. Thus, there is room for human error in that the incorrect amount of diluent may be added, thereby producing medication that has a concentration that is higher or lower than it should be. This can potentially place the patient at risk and furthermore, the reconstitution process can be very labor intensive since it can entail preparing a considerable number of medication syringes that all can have different medication formulations. This can also lead to confusion and possibly human error.
If the medication needs to be reconstituted, the medication initially comes in a solid form and is contained in an injectable drug vial and then the proper amount of diluent is added and the vial is agitated to ensure that all of the solid goes into solution, thereby providing a medication having the desired concentration. The drug vial is typically stored in a drug cabinet or the like and is then delivered to other stations where it is processed to receive the diluent.
Automated systems are typically configured to accept and operate with only single sized syringes and therefore, multiple devices are required when it is desired to fill syringes of different sizes since the systems are specific to one syringe size. It would therefore be advantageous if a single medication preparation system is configured to receive and handle syringes of multiple sizes.

Automated system and process for filling drug delivery devices of multiple sizes


In a lockup control apparatus and method for a vehicular torque converter, the torque converter is controlled to be under a steady-state lockup state by a lockup clutch during a steady-state traveling state, and the torque converter is controlled to be under a coast lockup state during a coasting state where an accelerator opening angle is completely closed, and a lockup state is released when an engine speed becomes equal to or lower than a predetermined lockup release rotational speed. Moreover, an actual lockup release time between a time point when a lockup release command for releasing the lockup state is outputted and a time point when the lockup clutch becomes completely released is calculated, and the lockup release rotational speed is set on the basis of the calculated actual lockup release time.

a) Field of the Invention
The present invention relates to lockup control apparatus and method for a vehicular torque converter with which an automatic transmission is provided, having a lockup mechanism for establishing a direct connection between input and output elements of the torque converter. Specially, the present invention relates to a lockup control for releasing a lockup (state) according to an engine speed while a vehicle is coasting (or, during a coasting state).
b) Description of the Related Art
The torque converter transmits a driving power between input and output elements of the torque converter via a working fluid. Hence, a power transfer efficiency in the torque converter is normally low although a torque fluctuation absorbing function and a torque increasing function are achieved. Therefore, a lockup-type torque converter, which is provided with a lockup clutch for establishing a lockup state where input and output elements of the torque converter are directly connected, is commonly used.
In the vehicle equipped with such a lockup-type torque converter, when the vehicle starts to coast with an accelerator opening angle being completely closed, the lockup state is generally applied so as to mainly improve an energy consumption. The lockup state in this situation is hereinafter called a coast lockup. In this coast lockup state, suppose that a lockup clutch engagement differential-pressure that is applied to the lockup clutch is kept the same high pressure as at the time of an ordinary lockup. In this case, when the vehicle rapidly decelerates and wheels are locked while coasting, a release of the lockup for the lockup clutch tends to be delayed. Hence, there is a possibility that an engine stall may be caused by the locked wheels.
With this fact taken into consideration, a Japanese Patent Application First Publication No. 1999-182672 published on Jul. 6, 1999 exemplifies a previously proposed lockup control apparatus in which the lockup clutch engagement differential-pressure (or, pressure-differential) in the coast lockup state (hereinafter, also called a coast lockup differential-pressure) is set to lower than the lockup clutch engagement differential-pressure of a steady-state lockup applied in (or, under) a steady-state traveling state or a slow accelerating state.
Namely, the lockup clutch engagement differential-pressure in the steady-state traveling state is set to be a high differential-pressure almost near a maximum differential-pressure in order to avoid a slipping of the lockup clutch. Then, after the vehicle begins to coast with the accelerator opening angle (detected by an accelerator pedal) being completely closed (detected by an idling switch), the lockup clutch engagement differential-pressure in the coast lockup state (or, the coast lockup differential-pressure) is controlled to be a sufficiently low differential-pressure within a range where the lockup clutch does not judder.
Moreover, a Japanese Patent Application First Publication No. 1999-159608 published on Jun. 15, 1999 exemplifies another previously proposed lockup control apparatus. The above-described Japanese Patent Application First Publication teaches that a controller determines whether the lockup clutch generates a minute slipping in the coast lockup state, and the coast lockup differential-pressure is so corrected (or, updated) and learned as to become smaller gradually while the minute slipping is not detected. In this previously proposed lockup control apparatus, after the process of the correction and learning proceeds enough, the coast lockup differential-pressure can become smaller close to a limit of a range where the minute slipping is not generated even if there is some disparity in a differential-pressure control system. Hence, the release of the lockup is quickly performed when the vehicle is braked suddenly.

Lockup control apparatus and method for vehicular torque converter


The present invention provides a composition comprising a green-yellow vegetable (e.g., broccoli, spinach, parsley, komatsuna (Brassica rapa L.), Japanese radish leaves) and a light-colored vegetable (e.g., lettuce, cabbage, celery), the composition having the following effects:    (1) inhibiting the generation of blood lipid peroxide;    (2) lowering blood TBARS levels or suppressing the elevation of blood TBARS levels;    (3) increasing blood vitamin E levels;    (4) enhancing blood antioxidant activity;    (5) enhancing blood TRAP levels;    (6) lowering blood active oxygen levels or suppressing the elevation of blood active oxygen levels; and    (7) preventing or treating diabetic complications.

Recent studies have revealed that lipid peroxides generated in the body cause various diseases. Therefore, various foods and pharmaceutical preparations for inhibiting lipid peroxide generation have been proposed (e.g., Japanese Unexamined Patent Publication No. 2000-198740).
In diabetic patients, active oxygen-induced blood and tissue disorders progress with increasing blood sugar. Such oxidation stress is known to cause the onset or aid the progress of complications such as arteriosclerosis and capillary disorders. Therefore, a method for preventing or treating diabetic complications by using antioxidants has been sought with the expectation of improving the oxidation state of blood and tissues.

Method of enhancing blood antioxidant activity ingesting a compound in the form of at least one form selected from amongst juice, powder, granule, tablet and capsule, which contains an effective amount of at least one vegetable selected from the group consisting of broccoli, spinach, parsley,


A lighting system for an electronic device comprising at least one movable lens to cover a light source.

Pulse width modulators (PWM) are commonly used to control the intensity or brightness level of a light emitting diode (LED) or other light. However, PWMs increase the cost and complexity of a system because of the additional circuitry and software instructions that are associated with managing the PWMs. Additionally, PWMs require additional power which in certain circumstances is scarce.

Hewlett-Packard Development Company, L.P.


A contact of an electric part socket has a first spring portion, a second spring portion spaced apart from the first spring portion but connected to it at both basal and distal ends thereof, a terminal portion leading to the connecting portion between the basal ends and adapted to be brought into contact with a wiring board or the like, and a contact portion formed on the connecting portion between the distal ends and adapted to be brought into contact with a terminal of an electric part to be engaged on it. The first and second spring portions are flexed about the connecting portion between the basal ends in order to displace the contact portion downward. The contact portion is pressure contacted with the terminal of the electric part mounted on it by reaction of the first and second spring portions.

1. Field of the Invention
This invention relates to a contact to be used for contacting with a terminal of an electric part such as an IC package.
2. Description of the Prior Art
A conventional contact 1, as shown in FIG. 9, often used in a socket for an IC, etc. comprises a supporting portion 2 extending in a horizontal direction, a terminal portion 3 extending downward continuously from the supporting portion 2 in order to be contacted with a circuit board or the like, a spring portion 4 disposed above the supporting portion in such a manner as to be continuous therefrom and curved into a horizontal generally U-shape, and a mount contact portion 5 formed on a free end of the spring portion in order to exert a vertical resiliency thereto and adapted to receive thereon an external terminal of an IC, the mount contact portion 5 being displaced downward while flexing the U-shaped spring portion 4 when the terminal of an electric part is contacted thereon and pressure is exerted thereto, so that the mount contact portion 5 is pressure contacted wtih the terminal of the electric part by reaction thereof.
In recent years, with the development of electronics manufacturing techniques, a small size of an IC socket is in demand. Furthermore, miniaturization of the contacts in an IC socket and of an external terminal of an IC has progressed, and as a result, achievement of a reliable contact relation therebetween is increasingly in demand at present. However, the conventional contact of the type in which a terminal of an electric part is contacted thereon in order to obtain an electric contact relation therebetween has such shortcomings that when the horizontal U-shaped spring portion is displaced in a vertical direction against its resiliency in order to exert contact pressure to the contact portion, the contact portion is disconnected from the external terminal of the IC because the contact portion has components which are excessively displaced forward and backward while it is itself displacing downward.
Since the space for accommodating the horizontal generally U-shaped spring portion is limited, even if the configuration of the spring portion is changed in order to reduce the amount of displacement of the contact portion in the forward and backward direction, control of the displacement of the contact portion in the forward and backward direction owing to the change in configuration thereof is necessarily limited.
Also, a conventional IC package called a TAB package has such shortcomings that since an external terminal thereof is a Cu foil which is soft, the strength thereof is very low and when the contact portion of the contact is displaced in an upward or downward direction, it is moved forward and backward while itself being friction contacted with the Cu foil, to thereby cause the weak external terminal to be deformed.


The output of a Radio Frequency (RF) Power Amplifier (PA) is sampled and down-converted, and the amplitude envelope of the baseband feedback signal is extracted. This is compared to the envelope of a transmission signal, and the envelope tracking modulation of the RF PA supply voltage VCC is adaptively pre-distorted to achieve a constant ISO-Gain (and phase) in the RF PA. In particular, a nonlinear function is interpolated from a finite number gain values calculated from the feedback and transmission signals. This nonlinear function is then used to pre-distort the transmission signal envelope, resulting in a constant gain at the RF PA over a wide range of supply voltage VCC values. Since the gains are calculated from a feedback signal, the pre-distortion may be recalculated at event triggers, such as an RF frequency change. Furthermore, the method improves nonlinearity in the entire transmitter chain, not just the RF PA.

Mobile electronic communication devices—including cellular telephones, pagers, smartphones, remote monitoring and reporting devices, and the like—have dramatically proliferated with the advance of the state of the art in wireless communication networks. Many such devices are powered by one or more batteries, which provide a Direct Current (DC) voltage. One challenge to powering electronic communication devices from batteries is that the battery does not output a stable DC voltage over its useful life (or discharge cycle), but rather the DC voltage decreases until the battery is replaced or recharged. Also, many electronic communication devices include circuits that operate at different voltages. For example, the Radio Frequency (RF) circuits of a device may require power supplied at a different DC voltage than digital processing circuits.
A DC-DC converter is an electrical circuit typically employed to convert an unpredictable battery voltage to one or more continuous, regulated, predetermined DC voltage levels, and thus to provide stable operating power to electronic circuits. Numerous types of DC-DC converters are known in the art. The term "buck" converter is used to describe a DC-DC converter that outputs a lower voltage than the DC source (such as a battery); a "boost" converter, also called a step-up, is one that outputs a higher voltage than its DC input. Both boost and buck converters may be implemented as switched mode power supplies (SMPS), in which energy is transferred from a source, such as battery, to a storage component, such as an inductor or capacitor, at a high frequency through transistor switches.
Supplying power to an RF power amplifier (PA) of an electronic communication device is particularly challenging. The efficiency of an RF PA varies with the amplitude of the transmission signal to be amplified. Maximum efficiency is achieved at full power, and drops rapidly as the transmission signal amplitude decreases, due to transistor losses accounting for a higher percentage of the total power consumed. The loss of efficiency may be compensated by a technique known as "envelope tracking," in which the output of a DC-DC converter, and hence the voltage supplied to the PA, is not constant, but is modulated to follow the amplitude modulation of the transmission signal. In this manner, at any given moment, the power supplied to the RF PA depends on the amplitude of the signal being amplified. Such modulation of the RF PA power supply can dramatically improve power consumption efficiency.
FIG. 1 depicts the relevant RF output portion of an electronic communication device 10. A battery 12 provides a battery voltage VBAT to an efficient, wide-bandwidth envelope-tracking power supply 14 that modulates the supply voltage of the RF PA 16. The RF PA 16 outputs an amplified RF signal for transmission from the device 10 on one or more antenna 18. The modulated voltage VCC(t) output by the dynamic power supply 14 should be capable of tracking a rapidly varying reference voltage. As such, the power supply 14 must meet certain bandwidth specifications. The required bandwidth depends on the specifications of the network(s) in which the RF PA 16 is used. For example, the required bandwidth exceeds 1 MHz for EDGE systems (8PSK modulation), and exceeds 30 MHz for LTE20 (Long Term Evolution).
The design of transmitters 10 employing envelope tracking power supplies 14 for RF PAs 16 is challenging, and requires the use of more sophisticated characterization techniques than is the case for designing traditional, fixed supply power amplifiers. The fundamental output characteristics of an RF PA 16 with an envelope tracking power supply—power, efficiency, gain, and phase—depend on two control inputs: RF input signal power and the supply voltage VCC.
A typical envelope tracking system dynamically adjusts the supply voltage VCC to track the RF input signal envelope at high instantaneous power. In this case, the PA 16 operates with high efficiency in compression. The instantaneous supply voltage VCC(t) primarily determines the PA 16 output characteristics. Unfortunately, this supply voltage modulation introduces an additional source of distortion that is due to the variations of PA 16 gain and/or phase as a function of the supply voltage VCC. FIG. 2A depicts variations in gain (AM-AM), and FIG. 2B depicts variations in phase AM-PM) with supply voltage VCC variations. In a conventional PA, supplied by a constant voltage, these variations are only linked to the variation of the RF input signal voltage.
FIG. 3A depicts the time-domain variations of the voltage VCC supplied to a PA 16 by an envelope tracing power supply 14, and FIG. 3B depicts the corresponding time-domain variations in the gain of the PA 16. These waveforms clearly show the dependency of the gain on supply voltage modulation. For example, large negative deviations, or drops, in supply voltage VCC correspond to very large decreases in gain. Moreover, this dependency is a nonlinear one, being significantly more pronounced as the supply voltage VCC is reduced. FIG. 4 depicts the PA 16 gain as a function of the supply voltage VCC, where again it is evident that low excursions of supply voltage VCC correspond to dramatic drops in the small signal gain of the RF PA 16. This modulation of the PA 16 gain impairs linearity of the PA 16.
In general, the transfer function for an amplified RF signal isVOUT(VCC,VIN)=GPA(VCC,VIN)·VIN  (1)where VIN is the magnitude of the RF PA 16 input signal, VOUT(VIN,VCC) is the magnitude of the output signal, VCC is the PA 16 instantaneous voltage from power supply 14, and finally GPA(VIN,VCC) is the gain of the PA. The gain GPA, and hence the output voltage VOUT, is a nonlinear function of VIN and VCC. Ideally, the gain should be constant.
The nonlinear gain GPA can be approximated by a two-dimensional polynomial.GPA(VCC,VIN)=b0+b1VCC+b2VCC2+ . . . +bβ-1VCCβ-1+bβVCCβ
with:
                                          b            0                    =                                    c                              0                1                                      +                                          c                                  1                  1                                            ·                              V                IN                                      +            …            +                                          c                                  α                  -                                      1                    1                                                              ·                              V                IN                                  α                  -                  1                                                      +                                          c                                  α                  1                                            ·                              V                IN                α                                                                                b            1                    =                                    c                              0                2                                      +                                          c                                  1                  2                                            ·                              V                IN                                      +            …            +                                          c                                  α                  -                                      1                    2                                                              ·                              V                IN                                  α                  -                  1                                                      +                                          c                                  α                  2                                            ·                              V                IN                α                                                                                …                                                                        b                          β              -              1                                =                                                    c                                  0                                      β                    -                    1                                                              ·                              V                IN                                      +            …            +                                          c                                  α                  -                                      1                                          β                      -                      1                                                                                ·                              V                IIN                                  α                  -                  1                                                      +                                          c                                  α                                      β                    -                    1                                                              ·                              V                IN                α                                                                                b            β                    =                                    c                              0                β                                      +                                          c                                  1                  β                                            ·                              V                IN                                      +            …            +                                          c                                  α                  -                                      1                    β                                                              ·                              V                IN                                  α                  -                  1                                                      +                                          c                                  α                  β                                            ·                              V                IN                α                                                                        (        2        )
FIGS. 5A and 5B depict how laboratory measurements (circles) of PA 16 gain vs. supply voltage VCC and RF transmission signal voltage, respectively, can be interpolated using the 2-D polynomial (continuous lines). Note that the phase shift of the PA 16 could similarly be written this way and interpolated by a 2-D polynomial.
The term "ISO-Gain" is used herein as a generic, descriptive term to denote a constant gain (GISO) in an RF PA 16, which does not change in response to variations in VCC and VIN. From equation (1), the gain can be written as:
                                          G            PA                                          (                                          V                CC                            ,                              V                                  I                                                                                N                                                      )                          =                                                            V                OUT                                                          (                                                      V                    CC                                    ,                                      V                    IN                                                  )                                                    V              IN                                =                                                                      V                  OUT                                                                  (                                                            V                      CC                                        ,                                          V                      IN                                                        )                                                            V                CC                                      ·                                          V                CC                                            V                IN                                                                        (        3        )
In envelope tracking operation the voltage VCC (from the voltage supply 14) is a linear replica of the envelope of an RF input signal multiplied by a constant α. As a result:
                                          G            PA                                          (                                          V                CC                            ,                              V                IN                                      )                          =                                                            V                OUT                                                          (                                                      V                    CC                                    ,                                      V                    IN                                                  )                                                    V              CC                                ·          α                                    (        4        )
In order to obtain a constant gain GISO over variations in both VCC and VIN, the following condition must be met:
                                                        G              PA                                                  (                                                V                  CC                                ,                                  V                  IN                                            )                                =                      G            ISO                                                                              so          ,                                    (        5        )                                          G          ISO                =                                                            V                OUT                                                          (                                                      V                    CC                                    ,                                      V                    IN                                                  )                                                    V                              CC                                                                                _                                                                                pred                                              ·                      α            .                                              (        6        )
This condition can be fulfilled by modifying the shape of VCC through a particular pre-distortion gain that depends on both VCC and VIN:VCC—pred(VCC,VIN)=VCC·Gainpred(VCC,VIN).  (7)
Substituting equation (7) into equation (6) yields an expression of the required pre-distortion gain:
                                          Gain            pred                                          (                                          V                CC                            ,                              V                IN                                      )                          =                              α                          G              ISO                                ·                                                    V                OUT                                                          (                                                      V                    CC                                    ,                                      V                    IN                                                  )                                                    V              CC                                                          (        8        )            FIG. 6 depicts the operation of ISO-Gain pre-distortion in the case where VCC is constant and VIN (or PIN) varies. The nonlinear gain applied to the supply voltage VCC is depicted in the lower curve, whereas the PA 16 gains with and without ISO-Gain pre-distortion are depicted in the upper two curves. The upper curve clearly shows that ISO-Gain operation allows maintaining the gain of the PA 16 relatively constant for a wide range of VIN (or PIN).
In practice, pre-distortion such as that depicted in FIG. 6 relies on testing and calibrations performed at chip fabrication. Pre-distortion parameters are calculated, and stored in large look-up tables (LUT). During operation, pre-distortion perturbations are retrieved from the LUTs and applied to the power supply 14. Accuracy is proportional to the size of the LUT; however, accuracy is limited because the necessary computation time is also proportional to the LUT size. Additionally, because all known envelope tracking RF PA power supply pre-distortion is "open-loop" and uses factory-generated values, the pre-distortion applied cannot be recalculated over the life of the circuit, such as to account for shifts in RF frequency, output power, temperature, component aging, and the like.
The Background section of this document is provided to place embodiments of the present invention in technological and operational context, to assist those of skill in the art in understanding their scope and utility. Unless explicitly identified as such, no statement herein is admitted to be prior art merely by its inclusion in the Background section.

Adaptive ISO-Gain pre-distortion for an RF power amplifier operating in envelope tracking


A multi-mode band-gap current reference includes a band-gap current mode module and an adjustable current source module. The band-gap current module provides a band-gap reference current and a voltage representation of the band-gap reference current. The adjustable current source module is operably coupled to produce a process-independent band-gap current and a voltage representation of the process-independent band-gap current. The adjustable current source module produces the process-independent band-gap current based on a difference between the voltage representation of the band-gap reference current and the voltage representation of the process-independent band-gap current.

1. Technical Field of the Invention
This invention relates generally to integrated circuits and more particularly to band-gap references.
2. Description of Related Art
Integrated circuits are used in an abundance of electronic devices ranging, for example, from handheld games to computers to communication systems to home appliances and beyond. Integrated circuits can be manufactured using a variety of processes including bipolar, CMOS, gallium arsenide, and silicon germanium. Of these processes, CMOS is the most popular due to its flexibility to support various circuit topologies, its circuit density (i.e., amount of transistors per die area), and its cost. CMOS integrated circuits, however, are not perfect. For instance, the performance of the components fabricated utilizing a CMOS process varies over temperature and also varies from integrated circuit to integrated circuit. Multiple techniques have been developed to compensate for these variations including match component designs, band-gap references, calibration circuits, et cetera.
Band-gap voltage references are used on almost every integrated circuit to provide a fixed reference voltage that does not drift over temperature and may be designed to be process variant independent or process variant dependent. Typically, a band-gap circuit is designed to provide a 1.2 volt reference that does not vary over temperature. This is typically done by taking advantage of the known temperature related properties of CMOS transistors. As is known, a base emitter voltage (VBE) of a CMOS transistor that is emulating a bipolar transistor decreases over temperature. As is further known, the slope of the VBE versus temperature curve varies based on the size of the transistor, where a smaller transistor has a greater slope than a larger transistor. Based on this property, a positive slope difference ratio may be produced over temperature between the two transistors of different sizes. This difference ratio may be scaled to have an equal but opposite slope of the VBE versus temperature curve for the smaller transistor. Utilizing these inversely proportional curves, a temperature independent band-gap voltage reference is achieved.
The band-gap voltage reference can be resistor-independent or resistor-dependent. The resistor-dependent band-gap voltage reference is one that produces a voltage that, from integrated circuit to integrated circuit varies due to process variations inherent in the CMOS integrated circuit fabrication process of producing resistors. Circuits whose operations are resistor-dependent use resistor-dependent band-gap voltage references. For example, an amplifier with resistive loads is a circuit whose operation is resistor-dependent. In particular, the process variations of the resistive load (i.e., the resistor value, for integrated circuit to integrated circuit varies) affect the gain of the amplifier. By utilizing a resistor-dependent band-gap voltage reference for such circuits, the process variations that affect the circuit also affect the band-gap voltage reference in a similar manner such that, from integrated circuit to integrated circuit, the circuit performs in a substantially similar manner.
A resistor-independent band-gap voltage reference is one that, from integrated circuit to integrated circuit, produces a substantially similar voltage reference. Circuits whose performance are not affected by process variations in fabricating resistors, but are dependent on an accurate voltage reference use resistor-independent band-gap voltage references. For example, analog-to-digital converters, digital-to-analog converters and other digital circuits are circuits that use a resistor independent bandgap voltage reference.
Many integrated circuits include circuits whose performance is resistor-dependent and circuits whose performance is resistor-independent. To accommodate both types of circuits, the integrated circuit includes two band-gap references: one that is resistor-dependent and one that is resistor-independent.
A band-gap voltage reference, whether resistor-independent or resistor-dependent, includes at least three stacked transistors per leg, which requires a supply voltage of at least 2.1 volts. Such a restriction presents a significant problem as the CMOS process evolves to allow integrated circuits to be powered from voltage sources of 1.8 volts and below. For these low supply voltage CMOS integrated circuits, the band-gap reference will not operate properly thus will not provide a reliable band-gap voltage reference.
Therefore, a need exists for a low supply voltage band-gap reference that can be extended to supply both a resistor-dependent band-gap reference and a resistor-independent band-gap reference.