A one-way clutch spring intended to reduce drag torque of one-way clutches. Tongues extend within pockets in which engagement members are disposed are bent in advance radially inward when they are disposed in an annular space so as to have bends at a proximal end and to form an angle of inclination (α) of 20°-30° with a base. Further, the angle of inclination (β) with the base increases to exceed the angle of inclination (α) by an amount of 5°-15° when engagement members contact the tongues. Further, the height of the front end of the tongue relative to the base is greater than that of a top of the second bend to the base, and the three bends each have their center of curvature positioned on the side of an inner ring with the base used as a reference and their radius of curvature is 0.2 mm-0.6 mm.

When power transmission and interruption between an inner ring and an outer ring are to be repeated, a one-way clutch is usually placed between the inner and outer rings.
FIG. 6(A) is a partial section view of a one-way clutch configured by a cage 3, a spring (ribbon spring) 16, and sprags 5 serving as engagement members, and FIG. 6(B) is an enlarged view of portion R in FIG. 6(A). In the one-way clutch, in order to enable the cage 3 to synchronize with the rotation of the outer ring, it is common to employ a configuration where a flange portion which is not illustrated, and which radially extends is disposed in, for example, an end portion of the cage 3 to provide a fastening zone, and the cage is pressingly inserted into the outer ring 1. One or two cages 3 (an outer cage and an inner cage) are used. In any case, the engagement members 5 (hereinafter, referred to as sprags 5) are placed in pocket 16p which are disposed on the spring 16 circumferentially at regular intervals, and urged in the engagement direction (wedge function direction) by tongues 16c disposed in the spring 16.
FIG. 7 is a partial perspective view of the spring 16, FIG. 8(A) is a plan view which is developed in the circumference direction of the spring 16, and FIG. 8(B) is a section view taken along the line A-A of FIG. 8(A) and a partial section view showing a state where the spring is actually placed in a one-way clutch (the sprags 5 are not placed).
In the spring 16, a thin metal plate member (for example, stainless steel), and bases 16a, 16a which are annular when incorporated, columns 16b, 16b, . . . which connect the base 16a and the base 16a, pockets 16p, 16p, . . . which are formed between the base 16a, 16a, . . . and the columns 16b and disposed circumferentially at regular intervals, and tongues 16c, 16c, . . . which elongate from center portions of the columns 16b toward the pockets are formed by press working. In this case, the configuration where the tongues 16c have tongues 16c which are previously inward bent before the spring 16 is placed in an annular space 4 has been conventionally known (see Japanese Utility Model Application (Kokai) No. HEI2-76234).
In each of the tongues 16c, three meandering bends (16d, 16e, 16f) are formed from a basal end portion of the column 16d. In such a case, usually, it is most frequent that, as shown in FIG. 9, the height d2 of a tip end portion of the tongue 16c to the base 16a is smaller than the height d1 of the second meandering bend 16e to the base 16a, and, in a state where the sprag 5 is urged, the height d2 of the tip end portion of the tongue 16c to the base 16a is larger than d1.
In a one-way clutch, a drag torque (friction torque) is inevitably generated in power transmission and interruption between inner and outer rings. In a one-way clutch, the drag torque depends on a spring force (spring constant) of a tongue of a spring which urges a sprag in the engagement direction. Specifically, when an urging force of a tongue is made large (a spring constant is made large), the engagement property of a sprag is good, but the drag torque is large. By contrast, when the urging force of the tongue is excessively small, the engagement property of the sprag is impaired, and an engagement failure occurs. Therefore, a one-way clutch in which a drag torque is made as small as possible while maintaining the engagement property is requested. Recently, from the viewpoint of energy saving, friction loss must be reduced, and, also in a sprag type one-way clutch, a drag torque must be reduced as far as possible. In a one-way clutch for a torque converter or the like, disengage type sprags are used, but reduction of a drag torque in a low rotation zone is not sufficient.
The invention has been conducted in order to cope with the above-discussed problems. It is an object of the invention to provide a one-way clutch spring which has a high engagement property, and in which a drag torque (friction torque) is considerably lower than the conventional one.


A backup power supply includes at least one ultra capacitor to store energy. The backup power supply includes a multiphase boost converter to provide a relatively constant voltage level from the energy stored on the at least one ultra capacitor. A charging and discharging controller is used to monitor the status of a power supply and control the charging and discharging of the ultra capacitors.

A backup power supply (also sometimes called an uninterruptible power supply) is a power supply that keeps computer hardware/software, medical devices or other sensitive or important electronics operating in the event of a power outage. Most backup power supplies serve to keep the hardware and software running for a few minutes until the hardware may safely be shut down or until a backup generator or other power source resumes providing power. Backup power supplies typically operate on a chargeable battery that provides power when the main AC power fails, thus making sure that the power to the hardware or electronics is uninterrupted.
In the past, several different types of chargeable chemical batteries have been used in uninterruptible power supplies. For example, Lead Acid chargeable batteries typically last about 2-4 years depending on environmental conditions like temperature, cycle use, and other variables. Recently, Lithium Polymer chargeable batteries have entered the market but they have similar life expectancies. All of the known chemical batteries, however, in addition to short lifespans, suffer from several other drawbacks including susceptibility to changes in temperature and shock, as well as overcharging and discharging inefficiency. Chemical batteries require significant maintenance and are potentially damaging to the environment when disposed of because they contain toxic chemicals. Moreover, traditional chemical batteries operate in a very narrow voltage range. For example, a 12 volt battery typically operates within a 3 volt range from approximately 10.7 volts to approximately 12.7 volts. Once a battery gets below 10.7 volts, any energy stored in the battery is not usable and is lost.
The ultra capacitor is a relatively new device and offers a new way of storing electric energy. Instead of storing energy electrochemically, it stores it in an electric field. Ultra capacitors have multiple advantages over conventional batteries, including a lifetime of over 10 years, resistance to changes in temperature, shock, overcharging, and discharging efficiency. They require less maintenance than conventional batteries and are light on the environment when disposed because they lack toxic chemicals. Their energy, however, is retrieved in the form of a voltage which decreases as the ultra capacitor discharges. Although the stored energy is retrievable, the use of an ultra capacitor in a backup power supply has not been achievable because the coupled electrical devices require a constant voltage level which the ultra capacitor, by itself, cannot provide.
Accordingly, a need exists for an uninterruptible power supply that uses a power source in the form of an ultra capacitor along with an accompanying circuit that together, form a reliable uninterruptible power source for providing backup power in the form of a constant voltage level.

Ultra-capacitor based uninterruptible power supply


An environmentally-friendly process for applying a chrome finish on a substrate is provided. The chrome finish comprises a thin film of aluminum and chromium deposited onto the substrate by physical vapor deposition (PVD) techniques. The thin layer can consist of three separately deposited metallic layers including a chromium layer sandwiched between a pair of aluminum layers or can consist of a single, simultaneously co-deposited layer of aluminum and chromium in a ratio of 10% to 70% by weight chromium and 30% to 90% aluminum. The structure of a coated substrate is also disclosed.

The present invention relates to a method for providing a chrome finish on a substrate, and more particularly, the present invention relates to a chroming process that is environmentally-friendly and that produces a rich, bright, reflective chrome coating traditionally desired by the automotive, furnishing, and other industries. The present invention also relates to a coated substrate having a chrome finish.
Conventionally, nickel/chromium and/or chromium is electroplated on aluminum and steel parts and provides an industry standard for a rich, reflective, chrome finish widely accepted, desired, and used in the automotive, furnishing and like industries. Chrome plating requires the use of hazardous solutions and bi-products that present numerous environmental issues and problems. In addition, since chromium is a very hard material, it is well known that a layer of material having high chromium content that is plated on a substrate tends to fracture or "craze" when the substrate is flexed and/or thermally expanded.
U.S. Pat. No. 6,399,152 B1 issued to Goodrich discloses a vacuum metalization process that can be used to apply chrome coatings on aluminum and steel substrates and that addresses the above referenced environmental concerns. The process requires vapor deposition of a nickel/chromium layer on a substrate, and thereafter, the separate vapor deposition of a chromium layer on the pre-deposited nickel/chromium layer. The result is a substrate having a decorative chrome finish that is of a color desired, and in some cases required, by the automotive industry. The coating is believed to provide good resistance to corrosion, and the process can be practiced without the environmental problems experienced in connection with plating processes. However, as stated above, layers of material having high chromium content tend to fracture or "craze" when the underlying substrate is flexed and/or thermally expanded. For example, see U.S. Pat. No. 4,374,717 issued to Drauglis et al. which discloses a method of sputtering a bright metal thin-layer finish on a molded plastic item, such as an automotive trim part. On column 1, lines 34–38, the Drauglis patent acknowledges the concern that thermal cycling can lead to delamination of the coating and that flexing a substrate can cause a sputtered layer to crack and peel.
U.S. Pat. No. 4,535,024 issued to Parker discloses a vapor deposited "black chrome" finish on external automotive trim parts, and U.S. Pat. No. 4,183,975 issued to Sidders and U.S. Pat. No. 4,131,975 issued to Blum et al. disclose sputtered coatings that provide the appearance of bright chromium metal traditionally used in the automotive industry and that possess the requisite corrosion and abrasion resistance for various automotive trim components. U.S. Pat. No. 6,068,890 issued to Käumle et al., U.S. Pat. No. 5,284,679 issued to Eisfeller et al., and U.S. Pat. No. 4,407,871 issued to Eisfeller disclose methods for applying high-stress resistant gloss coatings to articles, such as vehicle wheels, rims, bumpers, and grills, and U.S. Pat. No. 5,558,909 issued to Poliquin et al. discloses an apparatus and method for vapor depositing a metal layer on complex-shaped articles, such as automotive wheels and rims. U.S. Patent Application Publication No. 2004/0154539 A1 and U.S. Pat. No. 5,773,154 issued to Takada, U.S. Pat. No. 5,656,335 issued to Schwing, U.S. Pat. No. 6,326,057 B1 issued to Das et al., U.S. Pat. No. 3,801,357 issued to Baldi, U.S. Pat. No. 3,922,396 issued to Speirs et al., and U.S. Pat. No. 4,382,976 issued to Restall disclose other types of coatings and processes.
While the coatings and processes disclosed in the above referenced patents and published application may function in a satisfactory manner for their intended purposes, there remains a need for a environmentally-friendly process for providing a chrome finish on a substrate. The chrome finish produced by the process should have superior material properties and provide a desired chrome appearance traditionally accepted in the automotive industry.

Method for providing a chrome finish on a substrate


A slat arrangement for use with an apparatus that removes undesirable pieces from a plurality of pieces based upon size. The slat arrangement comprises a plurality of slats, wherein adjacent slats define a plurality of pockets.

1. Field of the Invention
The present invention relates to slats for removing undesirable pieces with an apparatus, and more particularly, to a slat arrangement wherein two adjacent slats define pockets for removing small or undesirable pieces with a small piece remover.
2. Description of the Prior Art
Often among a plurality of products, there are undesirable products. This can be true of manufactured items as well as agricultural items. For example, with vegetables such as, for example, baby carrots, pea pods, and carrot pieces, size is an important factor for determining desirability. In particular applications, certain sized carrot pieces, baby carrots or pea pods are unacceptable. Thus, smaller carrots and pea pods are removed.
A current machine for removing small pieces is a Small Piece Remover™ that is manufactured and marketed by Farmco, Inc., based in Redmond, Oreg. This device works with a plurality of adjacent slats, wherein each slat has a plurality of pockets defined therein. The slats are arranged in a side-by-side relationship along a looping conveyor. The device is set up at an angle such that a first side is higher than a second side. This angle is substantially perpendicular to the direction of travel for the plurality of slats.
In use, products, such as baby carrots, are placed on the slats. The looping slats are arranged such that they define a trough along the angled direction. The slats move and smaller baby carrots fall into the pockets while the larger, more desirable, baby carrots move through the defined trough until they fall off the device while the smaller carrots are carried by the pockets up and out of the defined trough and fall out of the pockets as the slats loop around. Thus, the smaller, more undesirable baby carrots are separated from the more desirable baby carrots.
Unfortunately, this slat design does not work well, especially with larger diameter baby carrots. Accordingly, an improved slat design and arrangement is needed.

Two-slat design for a small piece remover


In a repair method for a memory device, a process for determining whether or not repair is possible is first performed, following which processes are carried out for determining whether or not repair of failed lines is possible and whether or not repair of failed bits is possible. It is then determined whether or not a limit exists for a limbo portion, and if a limit exists, failure address connections of spare column portions are extracted from a buffer memory, and a rule check of the limbo portion and an adjustment of repair addresses is carried out in one-block portions for the obtained repair addresses.

1. Field of the Invention
The present invention relates to a repair method for a memory device that repairs failed cells of a memory device by using redundancy of spare rows or spare columns.
2. Description of the Related Art
A fault repair method of a memory device according to the prior art will be explained below with reference to FIGS. 1-4.
First, in Steps 11 and 12, it determined whether or not the device can be repaired based on information on the number of failed cells produced through device measurement. As shown in FIG. 2, the number of lines of spare columns and spare rows is Sc and Sr, respectively; and if the number of cells per row that can be repaired is r and the number of cells per column that can be repaired is c, then the maximum number of failed cells that can be repaired is (Sr.times.c)+(Sc.times.r)-(Sr.times.Sc). If the number of failed cells exceeds this maximum number of repairable failed cells, repair cannot be carried out.
If repair is possible, repair of failed lines is performed in Step 13. As shown in FIG. 3, the number of lines in a spare column and in a spare row is Sc and Sr, respectively, and the number of failed cells at row address r as seen from the column direction is Fr. If Fr>Sc, repair of all of the failed cells at row address r is not possible unless spare rows are used, and accordingly, row address r becomes one repair solution. This check is continued for row addresses and column addresses.
If repair is determined to be possible in Step 13, repair solutions are found, in Step 15, for the remaining failed cells by a round robin approach. Focusing on the repair of one failed cell, if both a spare row and a spare column exist, there are two repair solutions for the failed cell. In dealing with the next failed cell, if both a spare row and spare column exist, the two repair solutions for the preceding failed cell each have a further two repair solutions, for a total of four repair solutions. This approach is applied to all failed cells, and all possibilities are investigated to find the optimum repair solution having the smallest number of spare columns or spare rows. If a repair solution which is capable of repairing all of the failed cells cannot be found, then thr repair is impossible.
FIG. 4 shows repair solutions for a case wherein both the number of spare rows and the number of spare columns are three, and there exist eight failed cells. First looking at failed cell a, there are repair solutions in which a row address of failed cell a is repaired, and a repair solution in which a column address of failed cell a is repaired. Repair solution 1, Repair solution 2, Repair solution 3, and Repair solution 5 are solutions in which a row address of failed cell a is repaired, and Repair solution 4 is a solution in which a column address of failed cell a is repaired.
A repair solution in which a row address of failed cell a is repaired inevitably repairs failed cells b and c. Directing attention now to failed cell d, there are repair solutions in which a row address of failed cell d is repaired and a repair solution in which a column address of failed cell d is repaired. Repair solution 1, Repair solution 2, and Repair solution 3 are solutions in which a row address of failed cell d is repaired, and Repair solution 5 is a solution in which a column address of failed cell d is repaired. Similarly, Repair solution 1, Repair solution 2, and Repair solution 3 are solutions for failed cells g and h in which a row address of failed cell a and a row address of failed cell d are repaired.
According to the repair method of the prior art shown in FIG. 1, when failed cells (indicated by an "x") are present in a memory cell as shown in FIG. 5, the number of repair spare rows is five (their addresses being R1-R5) and the number of repair spare columns is two (their addresses being C1 and C2).
Because there are only four spare rows per block, one row of the five is repaired using the spare row A portion of the neighboring block, as shown in FIG. 6. For example, when the failed cells of addresses R2.sub.-- R5 are repaired by spare rows of the same block (block 1), and the failed cells of address R1 are repaired using the spare row of the neighboring block, the failed cell of address R1 indicated by a circle cannot be repaired. This is because the spare row B portion (referred to as the "limbo" portion) can only be used to repair a failed cell of a spare column of its own block.
As a consequence, repair of a device cannot be achieved despite replacement by the user of a defective site with a spare cell (spare row) based on a repair solution found by the repair method of the prior art.


A surface light source device and LCD employs a light guide plate which is capable of a three-dimensional emission direction controlling and avoids fine unevenness in brightness from appearing. Light guide plate 34 has a back face 34 provided with a great number of micro-reflectors 90 each of which has a guiding portion and a conversion output portion including a valley getting narrower and shallower as being distant from the guiding portion. The conversion output portion reflects input light P twice at inner slopes to produce inner output light Q. Inner output light Q is inner-incident to a slope of projection raw PR. While some of the inner incident light becomes directly escaping light, some other of the inner incident light fails to escape directly, reaching emission face 33 after travelling further along various light paths. Indirectly escaping light is emitted at second or later chances of emission. Directly escaping light and indirectly escaping light overlap, thereby preventing fine unevenness in brightness from appearing. It is advantageous to dispose reflector RF for increasing indirectly escaping light.

1. Field of Invention
The present invention relates to a light guide plate which is supplied with light sideways and deflects the light to output from an emission face, further relating to a surface light source device employing the light guide plate as well as to a liquid crystal display employing the surface light source device for back-lighting or front-lighting.
2. Related Art
A surface light source device of a type comprises a light guide plate having an end face, through which light is introduced, and two major faces (i.e. faces larger than end faces) one of which provides an emission face, being employed for various uses such as back-lighting or front-lighting for a liquid crystal display. Basic performance of surface light source devices of such type greatly depends on light guide plates employed therein.
A basic function of a light guide plate is to change a propagation direction (roughly in parallel with an emission face of the light guide plate) of light introduced into the light guide plate through a side end face so that the light is emitted through the emission face. As known well, a simply transparent light guide plate without any modification is capable of deflecting light little, providing unsatisfactory brightness. Consequently, any means for promoting emission through the emission face is required.
In general, means for promoting emission from a light guide plate relies upon one of the followings or some of them as combined:
(1) Scattering power within the light guide plate (light scattering guide plate);
(2) Emission face (a major face) provided with light diffusibility;
(3) Back face provided with light diffusibility;
(4) Emission face provided with light-refractive unevenness;and
(5) Back face provided with light-refractive unevenness.
Ways based on (1) provide uniform and highly effective emission with ease. However, the emission is subject to have a preferential direction much inclined with respect to a frontal direction. Usually, the inclination is about 60 to 75 degrees to a normal with respect to the emission face.
Accordingly, an element for modifying the inclined direction to the frontal direction (prism sheet) must be arranged. A light diffusion sheet, if alternatively employed, can bring some increase in frontal emission. However, light diffusion involves a loss of light because of divergence toward useless directions.
Ways based on (2) or (3) hardly provide a highly effective emission. The emission is also preferentially directed to oblique directions as in the case of (1). An increase light diffusibility checks the efficiency because of factors such as wide range scattering or absorption by light scattering elements (for example, by a white ink).
Although ways based on (4) are capable of causing light to escape from the emission face with ease, positive direction conversions are less effected. Accordingly, emission with a high efficiency is less expected. In particular, it is not advantageous that they fail to generate light rays which travel from the back face to the emission face.
To the contrary, ways based on (5) positively generate light which travels from a back face to an emission face of a light guide plate, being free from wide range light scattering. Accordingly, the ways are latently capable of effectively generating emission directed to roughly frontal directions.
FIG. 1a to FIG. 1c illustrate examples based on the above (5). Referring to the figures, reference number 1 indicates a light guide plate made of a transparent material such as acrylic resin, the plate having a side end face to provide an incidence face 2. A primary light source L is disposed beside the incidence face 2 to be supplied with light from the primary light source L. One of two major faces 3 and 4 of the light guide plate 1 provides an emission face 3. The other major face (called xe2x80x9cback facexe2x80x9d) is provided with a great number of recesses 5 having a cross section including slopes 5a and 5b.
The primary light source L emits light which is introduced into the light guide plate 1 through the incidence face 2. Upon encountering a recess, a propagation light within the light guide plate 1 (as represented by G1, G2) is inner-reflected by a slope 5a to be directed to the emission face 3. Inner-incidence angle is denoted by xcex8 and emission beams derived from beams G1, G2 are denoted by G1xe2x80x2, G2xe2x80x2. In other words, the slope 5a, which is relatively near to the incidence face 2 (or primary light source L) compared with the other slope 5b, provides an inner-reflection slope for direction conversion. This effect is sometimes called edge-lighting effect.
The recesses 5 are formed like dots or linear channels. As shown in FIG. 1a to FIG. 1c, formation pitch d, depth h or slope inclination xcfx86 of the recesses 5 is varied depending on distance from the incidence face 2. Such variations prevent brightness on the emission face 3 from varying depending on distance from the incidence face 2.
However, prior arts as shown in FIG. 1a to FIG. 1c are subject to the following problems.
1. Light is hard to reach a region behind the slope 5b as viewed from the incidence face 2. Therefore, a reduction of formation pitch d hardly rises direction conversion efficiency and the emission face 3 is apt to show an unevenness in brightness.
2. Sufficient direction control in a plane parallel to the incidence face 2 is not effected. For instance, if beams G1 and G2 are parallel to the emission face 3 but not perpendicular to the incidence face 2, emission beams G1xe2x80x2 and G2xe2x80x2 will be diverged to the right or left as viewed from the incidence face 2. Actually, there is considerable light components which propagate not perpendicularly with respect to the incidence face 2 within the light guide plate 1. Accordingly, it is difficult to provide an emission to a desirable angle or within a desirable angle range spatially (i.e. in both planes parallel and vertical to the incidence face 2).
3. Light leaking through the back face 4 occurs easily because direction conversion for generating light directed to the emission face 3 relies upon once-occurring-reflection (at slope 5a). That is, the condition for total reflection is broken with ease at the reflection for direction conversion. For instance, if beams G1xe2x80x2 and G2xe2x80x2 are required to be directed to approximately frontal directions, inner-incidence angle xcex8 is set at about 45 degrees. This is roughly the same as the critical angle for an interface between air and acrylic resin which is a typical material. Therefore, a considerable part of light propagating slightly downward leaks through the slope 5a.
The present inventor proposed a light guide plate and surface light source device/LCD employing the light guide plate, which were disclosed Japanese Patent Application Tokugan-Hei 11-38977. A brief explanation of the proposed technique is as follows, being aided by FIG. 2 and FIGS. 3a, 3b.
FIG. 2 is a plan view showing an arrangement of a surface light source device as viewed from a back side of a light guide plate arranged therein, the arrangement being disclosed in the above-mentioned patent application.
FIG. 3a is a partially enlarged perspective view of the light guide plate employed in the surface light source device shown in FIG. 2, and FIG. 3b is a partially enlarged view of one of projection-like micro-reflectors formed on a back face of the light guide plate. Note that sizes of micro-reflectors are exaggerated for the sake of explanation.
Referring to FIG. 2, a light guide plate 10 made of a transparent material. The light guide plate 10 has an end face (minor face) to provide an incidence face 12. A back face referenced with numeral 14 is a back face provided by one of major faces. The other major faces provides an emission face (See FIG. 3a). The light guide plate 10 has right and left side end faces (minor faces) 15 and 16.
A rod-like primary light source (cold cathode lamp) L is disposed along the incidence face 12 which is supplied with light from the light source. Both ends of the cold cathode lamp L are electrode portions EL1 and EL2 between which a light emitting portion extends with a length somewhat smaller than that of the incidence face 12. Such a design is often employed in order to avoid the electrode portions EL1, EL2 from sticking out.
According to a basic feature of the technique disclosed in the above patent application, a great number of projections 20 are formed on the back face 14.
The primary light source L emits light which is introduced into the light guide plate 10 through the incidence end face 12. An inner propagation light travels within the light guide plate 10 and is reflected generally twice when entering into one of the micro-reflectors 20, with the result that a light directed to the emission face 13 is produced. That is, the micro-reflectors function as xe2x80x9cdirection-conversion means for converting an input light into an inner output lightxe2x80x9d
As shown in FIGS. 3a and 3b, each of the micro-reflectors 20 is configurated as to be projected from a general plane (level plane) representative of the back face 14. The illustrated micro-reflector 20 has a shape like a projection having six faces 21, 22, 23, 24, 27 and 28.
The faces 21 and 22 provide a guiding portion to effect a smooth light input for direction-conversion. The faces 21 and 22 meet each other at a ridge portion 26. On the other hand, the faces 23 and 24 effect reflections twice for direction-conversion, producing an inner output light. The faces 23 and 24 meet each other at a ridge portion 25. The faces 27 and 28 are side walls limiting width of the micro-reflector.
Orientation of each micro-reflector is represented by an extending direction of the micro-reflector. In the illustrated example, the ridges 25 and 26 have a straight-projection-line provided by xe2x80x9cprojecting them onto the general plane representative of the back face 14xe2x80x9d. Arraying of the micro-reflectors is designed so that they align to a direction corresponding to light coming direction in order to rise input efficiency and direction-conversion efficiency.
A great part of input light represented by beams H1, H2 is incident to the incidence face 12 along a direction approximately perpendicular to the incidence face 12. However, light that is actually inputted into the projections is not precisely parallel to the general plane of the back face 14 but progresses somewhat downward (so as to approach the back face 14).
Light that progresses precisely parallel to the general plane of the back face 14 or approaches the emission face 13 advances deep without being inputted to projections 20. Consequently, the projections 20 do not obstruct light advancing and give no region little light reaches, thereby effecting contrary to recesses (See FIG. 1).
Viewing from the standpoint of the beams H1 and H2, the reflection faces 23 and 24 of the conversion output portion configurate a valley getting tapered forward. The ridge 25 corresponds to a bottom of the valley. The valley gets narrower and shallower according to distance from the guide portion. Therefore, a great part of light H1 and H2 entering the valley via the guide portion is inner-reflected by one of the reflection faces 23 and 24, and then inner-reflected again by the other faces 24 or 23.
As a result, a light propagation direction is converted twice three-dimensionally to produce inner output light J1, J2 directed to the emission face 13. The inner output light J1, J2 produce in such a way is emitted from the emission face 13 and used for illuminating an object such as LCD panel. Various variations of arrangement and orientation of the micro-reflectors 20 are allowed. The example shown in FIG. 2 is subject to the following rules.
1. Formation density (covering rate) tends to increase according to distance from the incidence face 12. This prevents brightness on an emission face from varying depending on distance from the incidence face 12.
2. Micro-reflectors 20 are arranged in corner areas A, B near to the electrode portions EL1, EL2 at a specially large density. This prevents, together with orientation of the following item 3, prevents dark areas corresponding to the areas A, B from emerging on the emission face.
3. Micro-reflectors 20 are orientated so as to be approximately vertical to the incidence face 12 almost over the back face 14, with their guide portions being directed to the incidence face 12. In other words, each micro-reflector 20 is orientated so that its conversion output portion has a ridge 25 which extends approximately at the right angle with respect to the incidence face 12.
4. In the corner areas A, B, micro-reflectors 20 are obliquely orientated with respect to incidence face 12, with guide portions being directed to the light emitting portion of the cold cathode lamp L. This causes these micro-reflectors 20 to be orientated corresponding to light coming directions, thereby rising direction conversion efficiency.
5. In both side edge portions 15, 16 except the corner areas A and B, micro-reflectors 20 are orientated so as to be inclined at small angles with respect to the incidence face 12, with guide portions being directed to the light emitting portion of the cold cathode tube L. This causes these micro-reflectors 20 to be orientated corresponding to light coming directions, as the above item 4, thereby rising direction conversion efficiency.
If conversion output portions (directions of inner reflection faces 23 and 24) of micro-reflectors 20 located in a certain range from both side end faces 15 and 16 are designed the so that an inner output light is inclined toward a center portion of the light guide plate 10, an emission with converging property is produced.
6. Micro-reflector arrangement does not have a strong regularity such that many micro-reflectors 20 align along a straight line. This makes the micro-reflectors 20 more inconspicuous. And besides, if incorporated in a liquid crystal display, the micro-reflectors can avoid from bringing Moire fringes which would be caused by an overlapping relation with a matrix-like electrode arrangement.
It is possible to heighten the performance of a light guide plate and surface light source device/LCD employing the light guide plate, which were disclosed in the above propose, by adding contrivances as above.
However, the above-proposed technique remains a problem unsolved. That is, the proposed technique, if applied, a fine unevenness in brightness appears on the emission face of the light guide plate 10 corresponding to size and arrangement pitch of the micro-reflectors 20. This gives a viewer a non-smooth visual feeling (a feeling of glaring).
This problem is supposed to arise due to a fact that a roughly almost of the inner output light of the micro-reflectors 20 escapes and is emitted from the emission face at the first chance with ease, as mentioned with referring to FIGS. 3a and 3b. In this Specification, such an escaping (light) at the first chance is called xe2x80x9cdirect escaping (light)xe2x80x9d
Needless to say, such direct escaping occurs generally corresponding to positions of the micro-reflectors 20. On the other hand, an efficient emission can not be expected in a blank region (a flat region on the flat back face 14) without micro-reflectors 20 among the micro-reflectors. As a result, a fine unevenness in brightness appears on the emission face.
In the instant Specification, the term xe2x80x9cindirect escapingxe2x80x9d or xe2x80x9cindirect escaping lightxe2x80x9d means a phenomena or escaping light which occurs or generates at second or later chances after being inner-reflected by the emission face. Simply saying, if the direct escaping light is produced to much as compared with the indirect escaping light, a fine unevenness in brightness will appear.
This problem will be relaxed to a degree by arraying the micro-reflectors 20 at a high density. However, arraying density is subject to a practical limit.
The present invention aims to overcome the above-mentioned problem of the proposed technique. Accordingly, an object of the present invention is to provide a light guide plate which is improved not only as to have a superior direction-conversion function for light introduced sideways but also as to hardly show a fine unevenness in brightness on an emission face.
Another object of the present invention is to provide a surface light source device which is improved as to produce an output illumination not only with a high efficiency but also with a high-quality involving little fine unevenness in brightness by means of the improved light guide plate. Still another object of the present invention is to provide a liquid crystal display which gives a high-quality display screen by applying the improved surface light source device to an arrangement for lighting a LCD panel.
The present invention is according to a basic idea (as proposed in the above patent application) that inner reflections caused twice at inner surfaces of a micro-reflector is a direction-conversion process, and, further to the basic idea, the present invention employs a great number of projection rows formed on an emission face as to cause the emission to have diversified traveling histories, thereby solving the problem.
In the first place, the present invention improves a light guide plate comprising two major faces to provide an emission face and a back face, and an incidence end face for introducing light.
According to a feature of the present invention, the back face of the light guide plate is provided with a great number of projection-like micro-reflectors for direction-conversion of light, each of which includes a guiding portion and a conversion output portion that includes a ridge portion and a pair of first and second reflection surfaces formed on both sides of the ridge portion respectively as to be inclined with respect to a general plane representative of the back face.
And the ridge portion and the first and second reflection surfaces form a valley in the micro-reflector, the valley tending to get narrower and shallower as being distant from the guiding portion.
Through this, an inner input light reaching the valley via the guiding portion is reflected by one of the first and second reflection surfaces and is further reflected by the other of the first and second reflection surfaces as to produce an inner output light directed to the emission face.
On the other hand, the emission face is provided with a great number of projection rows running approximately at right angles with respect to the incidence end face. This configuration causes some of the inner output light to escape through the emission face and the other to be inner-reflected.
The first and second reflection surfaces are inclined with respect to the general plane representative of the back face preferably at inclination angles different from each other, respectively. The ridge portion extends in a direction which may varies depending on location on the back face. A directional distribution of the emission from the emission face can be controlled depending on the inclinations of the first and second reflection surfaces and an extending-direction distribution of the ridges.
The present invention provides an improved surface light source device which employs the above-mentioned light guide plate. The present invention improves a surface light source device comprising at least one primary light source and a light guide plate having two major faces to provide an emission face and a back face, and an incidence end face for introducing light from the primary light source.
Corresponding to the above-mentioned features of the light guide plate, the back face of the light guide plate is provided with a great number of projection-like micro-reflectors for direction-conversion of light. Each of the micro-reflectors includes a guiding portion and a conversion output portion provided with a ridge portion and a pair of first and second reflection surfaces formed on both sides of the ridge portion respectively.
The ridge portion and the first and second reflection surfaces form a valley in the micro-reflector, the valley being configurated as to tend to get narrower and shallower as being distant from the guiding portion.
Through this, an inner input light reaching the valley via the guiding portion is reflected by one of the first and second reflection surfaces and is further reflected by the other of the first and second reflection surfaces as to produce an inner output light directed to the emission face.
On the other hand, the emission face is provided with a great number of projection rows running approximately at right angles with respect to the incidence end face. This configuration causes some of the inner output light to escape through the emission face and the other to be inner-reflected.
Through this function, direct escaping of the inner output light is controlled. A remarkable large part of the inner-reflected light, which has failed to escape, can have a chance of indirect escaping after travelling along various paths. There is only a slight correspondence between the locations of the micro-reflectors and the positions at which the indirect escaping occurs, with the result that the above-described fine unevenness in brightness renders inconspicuous.
It is preferable to dispose a reflection member along the back face of the light guide plate in order to increase the indirectly escaping light. The reflection member reflects and returns the light, which has been inner-reflected at the projection rows and leaked through the back face, to the light guide plate, thereby giving the light chances of indirect escaping.
Each conversion output portion may has a ridge extending in a direction which varies depending on location on the back face. as to approximately accord with a light coming direction. A directional distribution of the emission from the emission face may be controlled depending on the extending direction distribution of ridge.
Each ridge portion of a conversion output portion may extends in a direction which varies depending on location on the back face as to approximately accord with a light coming direction. Alternatively, Each ridge portion of a conversion output portion may extends in a direction which varies depending on location on the back face as to be inclined at a small angle with respect to a light coming direction.
The surface light source device improved as above may be adopted as a surface light source device for a backlighting-type LCD having a LCD panel illuminated from the back side or for a frontlighting-type LCD having a LCD panel illuminated from the front side (i.e. from the viewer""s side). In these cases, the performance of the surface light source device is reflected on that of the LCD. Thus, the LCD in accordance with the present invention has a display screen which looks well luminous.

Light guide plate, surface light source device and liquid crystal display


Disclosed are methods for optimizing financial transaction processing when a conventional financial transaction processing terminal is used with a wireless transmission system. An adapter is used between the terminal and a wireless modem, such as a CDPD wireless modem. The adapter receives from the terminal a data block from which the adapter recovers the requested type of transaction and relevant information about the transaction, such as a credit card number, transaction amount, etc., and formats all transactions into a common format for transaction processing. The common format includes a check code which may be used to detect changes made to the original data block as received from the terminal. The adapter then compresses the common format for wireless transmission. The goal of the use of the common format and the data compression is to fit the transaction request into a single data packet. A host computer receives the data packet, recovers the compressed common format and de-compresses the compressed common format to recover the common format. The common format may then be converted back to the original data block, as it was received from the terminal. The check code may be used to detect errors in compression, transmission and de-compression of the data block. The host computer processes the requested financial transaction and transmits a reply to the terminal, via the wireless modem and the adapter.

Conventional financial transaction processing methods and systems use a terminal, such as the ubiquitous Tranz 330 terminal manufactured by Verifone Corp., and a dialup telephone line to process financial transactions. A merchant provides the terminal, by entry of data on the keypad of the terminal and/or by running a credit or debit card through a magnetic track reader incorporated in the terminal, with information which describes a requested financial transaction. The terminal then uses the public switched telephone network to establish a connection with a host computer, transmits the information describing the financial transaction, receives a reply from the host computer relating to the requested financial transaction, acknowledges receipt of the reply from the host computer, and terminates the connection with the host computer. The terminal then provides, on its display, an approval or denial code or other relevant information relating to the requested financial transaction.
When the dialup connection is established between the terminal and the host computer, a path is established which allows data to be bi-directionally transmitted between the terminal and the host computer. Charges for dialup telephone access are assessed based on the type of call and the duration of the call. The dialup telephone access is often a "local" call, with no long-distance charges assessed. Some business phone lines, which a merchant might have, provide unlimited local calling, while other business phone lines are on measured service, wherein the duration of local calls is accumulated and used to calculate the phone bill. Occasionally the dialup access is provided via a "1-800" Wide Area Telephone Service (WATS) line, for the use of which the merchant is not directly charged by the phone company which provides the telephone service. Only rarely is the dialup access provided via a long-distance call. The dialup access is often a local call with unlimited service, or a measured-rate local call with a low per/minute billing rate. Thus, the duration of each telephone call to process a financial transaction and the amount of data that is transmitted in processing a financial transaction either do not affect the charges associated with the dialup telephone access or only produce minimal additional costs for the telephone service.
In contrast to local dialup telephone service, wireless telephone services, such as the analog or digital cellular telephone systems, and wireless data services, such as the Cellular Digital Packet Data (CDPD) network, assess charges based on the connection time or number of data packets that are transmitted.
Some attempts have been made to use conventional financial transaction processing systems and methods with analog cellular telephone services. One method involves coupling the audio signals between the financial transaction device and an analog cellular telephone via an acoustic coupler, with the merchant hand-dialing the phone number of the host computer on the cellular telephone keypad. Motorola has manufactured cellular telephones with a built-in telephone jack and circuitry which adapts the cellular telephone so that it may be operated as if it were a land-line telephone, and the financial transaction terminal could be connected to this cellular telephone and used without modification.
However, cellular telephone connections incur significant charges due to the lengthy time of cellular telephone connection establishment and the lengthy time which the connection must be maintained in order to process the financial transaction. The time during which the connection between the terminal and the host computer is being established may be charged for by the cellular carrier, which may result in charges for 10-20 seconds of cellular air-time for each transaction processing request even while no financial transaction processing is actively occurring. Additionally, many cellular carriers charge for connection time on a whole-minute basis, so that a cellular telephone call which had a duration of only 20 seconds may be billed at a rate as if the cellular telephone call lasted for an entire minute. If the cellular telephone call lasts for one minute and one second, the charge for the cellular telephone call may be billed at the rate for two whole minutes.
Simply changing from the analog cellular telephone system to a digital data system, such as the Cellular Digit Packet Data (CDPD) network, does not eliminate the additional charges incurred with a wireless transmission system. Even if the terminal could be made to directly address a CDPD wireless modem to provide a connection to the host computer, transmit the requested financial transaction and receive the response from the host computer, the conventional systems and methods of financial transaction processing would incur significant charges due to the number of data packets which are transmitted by conventional methods. Conventional methods may require packets to establish the connection between the terminal and the host computer and start the transaction process, one or two data packets to transmit the requested financial transaction, a data packet from the host computer to acknowledge receipt of a data packet from the terminal, one or two packets to provide the response for the requested transaction, one data packet to acknowledge receipt of the response from the host computer, and more data packets to close the connection. If there are transmission errors or synchronization errors which require re-transmission of data packets the total number of data packets per requested financial transaction rises further.
Conventional financial transaction processing systems and methods are not efficient when used with wireless transmission systems. What is needed is a method of optimizing financial transactions which are generated by conventional transaction processing equipment for efficient use with wireless transmission systems.

Apparatus and method for optimizing wireless financial transactions


A high-speed optical communications cell is integrated at the interior of a two-dimensional imaging array. The combined receiver and imager carries out both photodetection (converting photons to electrons) and circuit functions (e.g. amplifying and integrating the signals from the photodetectors). The high-speed receiver cell comprises a photodetector and a high-speed amplification circuit, providing an electrical output which can follow a rapidly varying optical signal falling on the photodetector. The imaging array comprises an array of photodetectors and readout circuits, providing an electrical representation of the variation of light with position across the receiver surface. The presence of an imaging array surrounding the communications receiver, and in the same plane as it, allows a single optical path to be used for source acquisition and tracking as well as for data reception.

Line-of-sight optical communication systems (LSOCs) are becoming increasingly important in a wide variety of applications. A typical LSOC comprises a laser transmitter for transmitting a modulated narrow beam of light through space or the Earth's atmosphere to a photodetector receiver. In space, line-of-sight optical communication to and from satellites is generally faster than radio communication and uses lighter equipment. On Earth, line-of-sight optical communication is free of spectrum regulation and is less susceptible to eavesdropping than radio. Moreover, the laser beam transmitters can be modulated at extremely high rates.
One difficulty that has delayed the full potential of LSOC systems is the necessity that the receiver and transmitter be very accurately pointed at one another to establish the desired link. Moreover, even after the link is established, the accuracy of pointing must be monitored and maintained over time. The system must adjust to the movement of satellites, the rotation of the Earth, and the vibration and sway of the transmitting and receiving stations. Any loss of pointing accuracy leads to a reduction or loss of signal that can substantially impair communication.
While there have been a variety of approaches to achieving the desired accuracy, none have proven completely satisfactory. One approach in terrestrial applications is to affix a spotting telescope to a data receiving telescope. The spotting scope allows a human operator to visually direct the receiver toward the transmitter. This approach, however, adds extra hardware to the system and requires human intervention. Moreover it requires precise alignment of the spotting scope with the axis of the data scope.
In space applications, added optical beacons can be used to direct added track sensors on the receiving satellite. The added beacons and sensors, however, increase the weight of the equipment and impose additional power demands on the satellite.
An alternative approach uses an imaging array, such as a CCD camera, to capture some of the light from the receiving telescope. The array feeds a signal to a computer which, in turn, analyzes the image and directs the telescope to the transmitter. This approach, however, requires that a beam splitter be placed in the main optical path, reducing the power available for data reception. It also introduces a second optical path that requires precise alignment of the beam splitter, the optical path to the detector and the optical path to the images.
Nor has the prior art found a completely satisfactory solution to the problem of maintaining pointing accuracy after lock-on. In the usual approach, a beam splitter is placed in the optical path and a fraction of the beam is diverted to a detector, such as a quadrant detector or imaging array, that is sensitive to the location of a laser spot on its surface. U.S. Pat. No. 5,770,850 granted to Bowen et al in 1998 and U.S. Pat. No. 6,522,440 granted to Poon et al in 2003 exemplify such systems. The beam splitter, however, consumes power and also introduces an additional optical path which must be precisely aligned. Furthermore, the position detector must be precisely located so that when the incoming data beam is perfectly centered on the data receiving photodetector, the split-off beam lies at the precise center of the position detector.
To avoid the latter difficulties in transmitter tracking, it has been suggested that the quadrant detector have a hole or window at its center, so that the majority of the incoming beam may pass through the hole or transmission window to a data detector located behind the detector. See U.S. Pat. No. 6,493,490 granted to Steiger in 2002 and U.S. Pat. No. 5,790,291 granted to Britz in 1998. This proposal, however, requires assembling the data photodetector with the quadrant detector and positioning the data detector accurately at the center of the hole or window. It also requires a separate solution to the problem of transmitter recognition and acquisition.
Accordingly there is a need for improved LSOC systems including a compact receiver that can be readily and continuously aligned with the transmitter.

Optical receiver comprising a receiver photodetector integrated with an imaging array