This invention is a method for converting fine particles of superabsorbent polymers into larger particles. The invention is primarily directed to aqueous solution processes for preparing superabsorbent polymers. In such aqueous solution polymerization methods, the polymerization reaction product is a high viscosity gel which is dried and ground into particles. In this grinding step, a portion of the product is produced as undesired fine particles having poor absorbency and poor fabrication properties; i.e. they "gel block" and dust. According to the invention, fine superabsorbent polymer particles (up to about 3 parts) are mixed with the high viscosity reaction product gel (100 parts) containing about 20 parts by weight of superabsorbent polymer and water (5 parts per part of recycled particles) to form a mixture with improved rheological properties. The resulting mixture can be processed at a higher rate than a reaction product gel of equal solids content which results in a higher product yield and increased productivity.

This invention relates to water-absorbent polymers which are known in the art as "superabsorbent" polymers. These polymers have the capability to absorb large volumes of aqueous fluids and find use in the manufacture of disposable diapers, sanitary napkins and incontinent devices. Superabsorbent polymers are prepared from at least one monomer having a polymerizable double bond which is water soluble or which becomes water soluble upon hydrolysis. Examples of such polymers are crosslinked, partially neutralized, polymers and copolymers of acrylic acid, starch grafted, polymers and copolymers of acrylic acid polymers and starch-polyacrylonitrile grafted polymers. The preparation of such polymers is well known in the art; see for example U.S. Pat. No. 4,076,663 which describes the solution polymerization of starch grafted, acrylic acid polymers.
Superabsorbent polymers are prepared on a commercial scale by solution or suspension or emulsion polymerization processes. In the suspension or emulsion methods, the monomer is polymerized in the form of droplets dispersed in a non-aqueous suspension medium and recovered as fine particles of spheres. In the solution method, the monomer is polymerized in water to produce a high viscosity gel which is extruded into strands or films which are dried to remove the aqueous polymerization solvent and ground into particles. In this grinding step, fine particles (<75 microns) are produced which are undesired because they have poor fluid absorbency properties and they cause dusting problems in the fabrication processes for preparing end products. This invention is directed to polymers prepared by the solution polymerization method. It is the object of this invention to recycle undesired fine particles produced in the grinding step and to reform them into larger more useful particles.

Process for the conversion of fine superabsorbent polymer particles into larger particles


A computer-assisted method for detecting copyright protection in digital images receives a digital image, searches for capture device information associated with the digital image, calculates one or more image characteristics of the digital image, and verifies copyright ownership and usage authorization of the digital image in response to the capture device information and the calculated image characteristics.

Advancement of digital imaging technologies have provided consumers unprecedented convenience in capturing, editing, and manipulating hardcopy and digital images. Inexpensive hardware and software tools are now available to allow ordinary consumers to digitize an image on a hardcopy media such as a reflective print or a photographic film, store the output digital image in a computer memory media, manipulate and edit the digital image, and reproduce the digital image using a digital printer. The commercially available digital scanners and digital printers now have such high resolution and high bit depth for each color plane that a consumer can easily reproduce a hardcopy image to achieve an image-quality level similar to the original image print. The ubiquitousness of this capability, however, has posed a threat to the protection and enforcement of the copyrighted images created by professional photographers.

This patent is subject to a terminal disclaimer.

Automated verification of copyrighted digital images


A communication network and its user i has a device for implementing a common key cryptosystem, an identifier of the user i represented by ID.sub.i which is made public in the network, an authentication key of a user i represented by S.sub.i is known only to the network and the user i and these identifiers and authentication keys of all the users are stored in a database of the network. Data for authentication and encrypted data of a cipher key for the subsequent privacy communication are sent from the network to the user, the user presents his identifier (ID) to the network, after which up to three interactions take place between the network and the user to perform the required authentications and distribution of the cipher key.

The present invention relates to information or data security technology for communication networks and, more particularly, to a mutual authentication/cipher key distribution system which prevents abuse of the network in a personal mobile communication system.
The technology for information security of the system in the communication network is roughly divided into (a) a user authentication technique which prevents an unauthorized access to the network by making a check to see if a user is an authorized one, and (b) a cryptographic technique which conceals communication contents on the circuit being actually used, thereby preventing eavesdropping by a third party.
With respect to the authentication technique (a), CCITT has proposed, as an authentication technique for future personal communication technology, a system such as shown in FIG. 5, in which the network and all users employ identical encryption devices and the network authenticates the users individually without presenting or revealing their passwords or similar personal secret information on the circuit. Let the identifier of a user i and his authentication key be represented by ID.sub.i and S.sub.i, respectively, and assume that S.sub.i is an authentication key known only to the network and the user. When the user i uses the network, he present first the information ID.sub.i to the network. Then the network generates a random number r.sub.u and sends it to the user i. The user i encrypts the random number r.sub.u with the encryption device using the authentication key S.sub.i as a secret key and sends the encrypted random number back to the network. Finally, the network fetches the authentication key of the user i held therein, similarly encrypts the random number r.sub.u using the fetched the authentication key as a secret key and, when the value of the thus encrypted random number matches with the value of the encrypted random number from the user i, authenticates the user i as an authorized user. This system requires a total of three interactions between the user and the network, including the presentation of the identification of the user to the network.
Besides, to prevent eavesdropping by the outsider (b), some key distribution system is used to implement key sharing between the network and the user. Finally, the shared key is used to encrypt correspondence and then communication starts between them.
As mentioned above in connection with the prior art, attention has been directed primarily to the function that the network authenticates the user. This is because the system has been designed on the understanding that the network is always correct or HONEST. In personal communication, however, since it is supposed that a base station, which covers a very narrow communication range, effects a position registration accompanying the communication with the user or his migration, there is a possibility that an abuser sets up a false base station and accesses the user via a radio channel. In such a situation the user will use his authentication key as a key to encrypt a proper numeral intentionally chosen by the false network and send it back thereto. This is what is called a chosen plaintext attack, which is the strongest one of various attacks on the cryptosystem. It is pointed out in a literature (E. Biham and A. Shamir: "Differential cryptanalysis of DES-1 like cryptosystems," '90 EUROCRYPTO, August 1990) that there is the likelihood that according to the choice of the cipher system, user's authentication key would be revealed by several rounds of such a chosen plaintext attack. Moreover, since a plurality of traders will provide personal communication services in the future, it will be necessary to make provision for enabling a user to correctly recognize the trader whose services are being used by the user.
Besides, the conventional system requires further interactions between the network and the user for the distribution of a key which is needed to hold cipher communication.

Mutual authentication/cipher key distribution system


A pharmaceutical composition for external use, including: i) luliconazole represented by the following structural formula (1) and/or a salt thereof; and ii) one or two or more selected from N-methyl-2-pyrrolidone, propylene carbonate, and crotamiton.

The Japanese archipelago extends from a subtropical zone to a temperate zone and has a warm climate high in humidity, which is liable to facilitate propagation of fungi such as molds. In addition, due to westernization of clothes, people are now accustomed to wearing shoes on feet. Accordingly, a foot serves as a favorable environment for the propagation of the fungi, leading to mycotic skin diseases that are serious social issues nowadays. Of those, onychomycosis has a low complete cure rate and high relapsing and reinfection rates. Therefore, an effective therapy has been demanded.
Conventionally, treatments mainly using tolnaftate formulations have been conducted on such diseases. In recent years, imidazole-based antifungal agents, such as bifonazole and itraconazole, are mainly used.
As the imidazole-based antifungal agents, there are commercially available imidazole-based antifungal agents such as those represented by the general formula (1) described below, specifically, luliconazole represented by the structural formula (1) below and lanoconazole represented by the structural formula (2) below. A commercially available product called "Lulicon" (registered trademark) is also present (e.g., see Patent Document 1 and Patent Document 2).
The luliconazole is an imidazole-based antifungal agent having optical activity with a wide antifungal spectrum, in particular, shows remarkable antifungal activity against dermatophytes. In addition, the luliconazole is also characterized in that its retention in the stratum corneum is extremely high, and thus is a compound expected to be applied to treatment of onychomycosis. Like other imidazole-based antifungal agents, however, luliconazole and lanoconazole are agents having problems in their solubility, so there is a need of using a solvent for their preparation. On the other hand, in some cases, the characteristic features of luliconazole may include a risk of a decrease in its optical purity when it is stored in a dissolved state under severe circumstances due to a type of a solvent used for dissolution, temperature, acid and base, or the like. Besides, such a decrease in optical purity may relate to a solvent. In other words, with regard to a pharmaceutical composition for external use containing luliconazole and/or a salt thereof, it is desirable to provide means for increasing the solubility thereof while suppressing a decrease in optical purity even under severe environment.
A decrease in optical purity is a common phenomenon, which sometimes occurs in an optically active compound according to storage conditions, particularly under severe conditions at high temperature. However, no means for suppressing the phenomenon is known.
Heretofore, in a pharmaceutical technology for antifungal agents, various studies have been conducted for increasing the solubility thereof (see, for example, Patent Documents 3 to 5). However, the antifungal agents to be dissolved show increases different in their solubility. Therefore, the effect of one of them cannot be directly applied to the other compounds. Among the solvents, a solvent that acts to prevent the optically active compound from a decrease in optical purity has not yet been known.
On the other hand, as a pharmaceutical preparation containing luliconazole and/or a salt thereof, a pharmaceutical preparation containing a film-forming agent and a polyoxypropylene/polyoxyethylene copolymer has been known (see, for example, Patent Document 6), but one containing N-methyl-2-pyrrolidone, propylene carbonate, or crotamiton has not been known at all. In addition, a basic process for manufacturing an imidazole-based compound is also already known in the art (see, for example, Patent Document 7):
where X represents a hydrogen atom or a chloride atom.

    Patent Document 1: JP 10-226686 A    Patent Document 2: JP 2-275877 A    Patent Document 3: JP 5-306223 A    Patent Document 4: JP 7-206711 A    Patent Document 5: WO96/11710    Patent Document 6: WO03/105841    Patent Document 7: JP 62-93227 A

Pharmaceutical composition for external use


Ester compounds having formula (1) wherein R1 is fluorine or C1-C10 fluoroalkyl, R2 is C1-C10 alkylene or fluoroalkylene, and R3 is an acid labile group are novel. They can be polymerized into polymers which are used to formulate resist compositions, which are processed by the lithography involving ArF exposure, offering many advantages including improved resolution and transparency, minimal line edge roughness, improved etch resistance, and especially minimal surface roughness after etching.

In the recent drive for higher integration and operating speeds in LSI devices, the pattern rule is made drastically finer. The rapid advance toward finer pattern rules is grounded on the development of a light source of a shorter wavelength, a projection lens with an increased numerical aperture (NA), and a resist material with improved performance.
With respect to the light source for exposure, the change-over from i-line (365 nm) to shorter wavelength KrF laser (248 nm) enabled mass-scale production of DRAM with an integration degree of 64 MB (processing feature size ≦0.25 μm). To establish the micropatterning technology (processing feature size ≦0.2 μm) necessary for the fabrication of DRAM with an integration degree of 256 MB and 1 GB or more, the lithography using ArF excimer laser (193 nm) is under active investigation. Although F2 laser (157 nm) is also considered as one candidate light source of shorter wavelength, the use of F2 laser is postponed because of many outstanding problems including a more expensive scanner.
With respect to the increase of NA, not only an improvement in lens performance is sought for, but also the immersion lithography which can establish an NA of 1.00 or greater by filling a high refractive index liquid between a lens and a wafer is of great interest. See Proc. SPIE, Vol. 5376, p44 (2004), for example. For the ArF immersion lithography now under investigation, it was proposed to apply to the 45-nm node by filling the space between the lens and the wafer with deionized water having a refractive index of 1.44. See Proc. SPIE, Vol. 5040, p724 (2003), for example.
With respect to the resist material, since the development of acid-catalyzed chemical amplification positive working resist materials as disclosed in USP 4,491,628 and USP 5,310,619 (JP-B 2-27660 and JP-A 63-27829), it has become possible to achieve a higher resolution and sensitivity. They now become predominant resist materials adapted for deep UV lithography. Of these, the KrF resist materials enjoyed early use on the 0.3 micron process, passed through the 0.25 micron rule, and currently entered the mass production phase on the 0.18 micron rule. Engineers have started investigation on the 0.15 micron rule. The ArF resist is expected to enable miniaturization of the design rule to 0.13 μm or less.
Various alkali-soluble resins are used as the base resin in such chemically amplified resist compositions. Depending on a light source selected for light exposure, a base resin of different skeleton is used. For KrF resists, a polyhydroxystyrene resin having phenolic hydroxyl groups as the alkali-soluble group is now a standard base resin.
For ArF resist materials, since polyhydroxystyrene resins and novolac resins have very strong absorption at a wavelength around 193 nm, studies were made on poly(meth)acrylate resins and resins comprising cycloaliphatic olefin such as norbornene as polymerized units, both using carboxyl groups as the alkali-soluble group (see JP-A 9-73173, JP-A 10-10739, JP-A 9-230595 and WO 97/33198). Of these, the poly(meth)acrylate resins are expected to reach a practical level because of ease of polymerization. One of the poly(meth)acrylate resins proposed thus far is a poly(meth)acrylate resin having methyladamantyl groups as the acid labile group and lactone rings as the adhesive group as disclosed in JP-A 9-90637. Norbornyl lactone is also proposed as an adhesive group having enhanced etching resistance as disclosed in JP-A 2000-26446 and JP-A 2000-159758.
The serious problems left unsolved for ArF resist materials are reduction of line edge roughness and enhancement of etching resistance. In general, a higher light contrast leads to a less line edge roughness. For example, increased NA of lens, application of modified illumination or phase shift mask, or wavelength reduction allows the light contrast to be increased, resulting in a reduced line edge roughness. Thus the wavelength reduction from KrF to ArF excimer laser is expected to reduce line edge roughness. However, it is reported that ArF resists actually have greater line edge roughness than KrF resists and that image contrast is in inverse proportion to line edge roughness. This is attributable to the difference in performance between ArF and KrF resists. See Proc. SPIE, Vol. 3999, p264 (2000), for example.
The use of an alternating copolymer as the base is proposed as one means of minimizing the edge roughness of pattern after development. See Proc. SPIE, Vol. 5039, p672 (2003), for example. The alternating copolymer having an ordered arrangement of recurring units within the polymer chain is characterized by its ability to minimize edge roughness, as compared with random copolymers and block copolymers.
One candidate of alternating copolymers that can be used as the ArF resist is a copolymer of norbornene and maleic anhydride as described in JP-A 10-10739. However, the resist using this copolymer suffers from storage instability and the like, and it remains unexpectable when this resist will be reduced to commercial practice. Another candidate is a copolymer of norbornene and α-trifluoromethylacrylate, which was the base polymer candidate for F2 resist. See Proc. SPIE, Vol. 4345, p273 (2001), for example.


A retraction device includes: a spindle, a support plate and a plurality of spring washers. The spindle is movable along an axis direction thereof and has a first end; a support plate has a fixed position, the first end of the spindle penetrates the support plate; and the plurality of spring washers are fitted over the first end of the spindle and stacked together in an identical direction. The plurality of spring washers are compressed between the spindle and the support plate with a predetermined pre-load. The spindle is configured to be switchable between a first position and a second position, and capable of moving a predetermined distance relative to the support plate in the axis direction of the spindle during switching. When in the first position, the spindle is farthest from the support plate, when in the second position, the spindle is closest to the support plate.

In a rotary microtome of the related art, the rotary microtome usually includes an object carriage for carrying a specimen holder which holds a specimen to be cut. The object carriage moves up and down in a vertical path of the rotary microtome. During the vertical movement, the specimen passes through a cutter fixedly arranged on the rotary microtome from an upper position to complete one section. After one section, the specimen holder is located under the cutter.
When the specimen is moved back to the upper position, its surface will hit the cutter and the specimen may be damaged. Therefore, a micro feeding mechanism for the rotary microtome has a retraction device. The function is realized by a pair of spring washers and a pull rod. When retraction is needed, the pull rod is pulled to pull the feeding mechanism back, and when the retraction is not needed, the pull rod is released, such that the feeding mechanism is moved to an original position by the pair of spring washers. The micro feeding mechanism in the related art refers to that the micro feeding mechanism can drive the specimen to feed 0.1 μm to 100 μm by turning a handwheel one circle.
In general, the pair of spring washers are usually arranged face-to-face and have low rigidity, such that the micro feeding mechanism does not have good rigidity. The micro feeding mechanism will vibrate when cutting a hard material or cutting at a high speed, and thus the quality of the section will not be good enough.

Retraction device and feed mechanism having the same


A current-control profile may be built from a sequence of phases in which the current is controlled in a defined manner. The electrical behavior of these phases may be configured within a list, which contains one entry, or slot, for each phase and which may be stored in a memory device. The order for stepping through the list is not hard-wired into the control circuit. Instead, such an order is part of the configuration for each entry, or slot, itself. Each entry/slot contains the information about the next phase, or the next possible phases depending upon the occurrence of any trigger events. In this way, the list of entries/slots is linked dynamically by the configuration thereby allowing for generation, in a flexible way, of current profiles with different characteristics and different numbers of phases and sequences.

FIG. 1 shows an example of a prior art current-control profile having 8 current-control phases, namely, off, pre-charge, peak, clamp0, hold0, clamp1, hold1, and off. A control signal, referred to in FIG. 1 as NON, is also shown. The control signal is de-asserted (High) during the first and second off phases and is asserted (Low) during the other phases. As is the case for all of the signals discussed herein, the polarity (i.e., whether the signal is asserted when it is high or when it is low) of the control signal shown in FIG. 1 is not significant (i.e., the polarity could be reversed instead).
Two conventional control approaches are known for generating such current-control profiles.
A fixed state-machine approach, which typically provides limited flexibility. FIG. 2 shows a fixed state-machine 200 that controls electrical current supplied to the target device 202 in accordance with the prior art.
The sequence of current phases is hard-wired into the control circuit allowing configuration of the parameters of the built-in phases only. As used herein, the terms "hardwired" and "implemented in hardware" refer to control-unit functionality that is implemented through use of sequential logic units, featuring a finite number of gates that can generate specific results based on the inputs to the control unit. According to a fixed state-machine approach, possible current profiles are limited to the phases and sequences known at time of control circuit design. This approach shows a limited flexibility in terms of building new current profiles.
A micro-sequencer approach typically provides undefined safety behavior. FIG. 3 shows a micro-sequencer 300 that controls electrical current supplied to the target device 202 in accordance with the prior art.
The behavior of the control circuit is determined during run-time by means of a code sequence as in the case of a micro-controller (e.g. software-based approach). Since the behavior of the control circuit is based on software, it is difficult, and potentially impossible, to prove an appropriate operation under all circumstances, such as a deactivation of the solenoid after a specified time after the control signal is de-asserted. Further, in a micro sequencer-based implementation, individual functions, such as turn-on and turn-off of an NMOS (n-channel metal oxide semiconductor), comparing the injector current to defined thresholds, reacting if current thresholds are crossed, comparing phase time with defined set point, and reacting if phase time has elapsed, are normally implemented in embedded microcode, which is typically very complex but versatile. A shortcoming of this approach lies in its complexity. For example, a typical program sequence for threshold detection might be as follows: 1. Program the comparator reference to the desired value. 2. Set up and enable an interrupt to be triggered when the comparator level has been satisfied. 3. Push variables associated with this function onto a stack or otherwise store them for later retrieval. 4. Branch to a wait loop or resume other processing. 5. When the comparator interrupt has fired, branch to the interrupt processing routine. 6. Retrieve the variables associated with this function from their storage location. 7. Turn on (or off) the output associated with the current control channel. 8. From within the interrupt, flag that the comparator has tripped, so that a new phase may be entered by the main program if necessary. 9. Load a new comparator reference level for the next step in the current control loop. As this sequence demonstrates, testing and verification of a complex software/hardware system can be extremely difficult because the system is essentially unbounded and is capable of doing many different types of things, it has the potential of doing many different things incorrectly. Problems usually result when external events happen at exactly an inappropriate time, exactly in an inappropriate order, or both, which can be very difficult to simulate in testing. We have all seen cases of software "locking up," becoming confused, or generally causing issues in embedded systems (cell phones, tablets, GPS, etc.). While this behavior is merely annoying when your cell phone needs to be restarted, it can be catastrophic in the case of a controller for a vehicle fuel injection system.
The fixed state machine approach avoids these problems by following the same sequence every time, with no possibility for changes to the sequence. Relative to a micro sequencer-based approach, the fixed state machine type of system is much easier to verify and validate, because external events have much less influence. But this ease of testing and validation comes at the expense of versatility in that the fixed state machine is only capable of following the sequence it was designed for. So any sequence changes need to be provided for at the time of the control circuit design.
A current-control circuit, also referred to herein as a current controller, that overcomes the shortcomings mentioned above would advance the state of the art.

Current controller having programmable current-control parameters and hardware-implemented support functions


A method for controlling a receiver circuit and circuit with a receiver circuit and with a control circuit is provided, whereby a received signal is demodulated and filtered. An amplitude value of the demodulated and filtered signal is compared with thresholds of a window comparator. A zero crossing of the demodulated and filtered signal is compared with time thresholds of a time window by a comparison unit. A first output value of the window comparator and a second output value of the comparison unit are logically combined, and wherein, via the logical combination, the receiver circuit is turned off if, within a period of time, the amplitude value is determined to be outside a window formed by the thresholds of the window comparator, or a zero crossing is determined to be outside the time window.

1. Field of the Invention
The present invention relates to a circuit and a method for controlling a receiver circuit.
2. Description of the Background Art
By means of a receiver circuit, a radio connection can be implemented between a transmitter and a receiver having the receiver circuit. The receiver circuit may be operated with a battery, for example. In this context, the longest possible operating life using the battery is desirable, wherein the operating life depends on the capacity of the battery and the power consumption of the receiver circuit.

Circuit and method for controlling a receiver circuit


The invention provides an illumination optical system that reduces polarization dependency of a light separation characteristic of a 45 degree dichroic surface and improves the image quality of the projector based on the color separation/synthesis optical system using the 45 degree dichroic surface. In the illumination optical system, green light and blue plus red light can be separated by a color light direction change element, and the polarization direction thereof are adjusted by a polarization change element.

1. Field of Invention
The present invention relates to an illumination optical system which uniformizes in-plane illuminance distribution of the light emitted from a light source, and to a projector having such an optical system.
2. Description of Related Art
Currently, for liquid crystal projectors, so-called three-plate type reflective liquid crystal projectors, which use three reflective liquid crystal panels, is known. The three-plate type reflective liquid crystal projector separates the light emitted from a light source into lights of three colors, that is, three primary colors, red (R), green (G), and blue (B) by a color separation system. Then the separated three color lights illuminate three reflective liquid crystal panels for each color light, the three primary colors modulated by each of the reflective liquid crystal panels are synthesized, and the color image obtained by the synthesis is projected, in an enlarged form, onto a screen by the projection lens.
In the above-described reflective liquid crystal projectors, miniaturization of the apparatus is considered to be important, so that optical elements having dichroic planes disposed at 45xc2x0 to the optical axis are often used for color separation and color synthesis. However, these projectors have a problem in that chrominance non-uniformity often occurs: by the polarization dependency of light separation characteristics of dichroic planes, thereby making it difficult to improve image quality.
Under this circumstance, several optical systems, which seldom cause chrominance non-uniformity in consideration of the characteristics of dichroic planes, and thus realize image quality improvement, have been proposed. For example, in Japanese Unexamined Patent Application Publication Nos. 7-84218 and 11-64794, optical systems have been proposed, in which a polarized beam splitter having a wavelength selection retardation film and a light separation function are used instead of dichroic planes for light separation. However, there remains a problem in that with a polarized beam splitter having a wavelength selection retardation film and light separation function, it is difficult to realize light separation which varies steeply, and that the cost becomes too high.
Accordingly, it is an object of the present invention to provide an illumination optical system which efficiently generates illumination light having specific color light with the polarization direction which is different by 90xc2x0 to the polarization direction of the other color light, so that such illumination light can provide the illuminated area with uniform illuminance distribution. Furthermore, it is another object of the present invention to provide a projector to which such an illumination optical system is applied, thus in which the polarization dependency of dichroic planes which constitute the color separation/synthesis optical system is reduced, and high quality projection image is displayed.
According to a first aspect of the present invention, there can be provided an illumination optical system including a luminous flux division optical element which divides the light from a light source into a plurality of partial luminous fluxes and collects each partial luminous flux, a color light separation optical element which separates each of the partial luminous fluxes into first color partial luminous flux and second color partial luminous flux, and emits the first color partial luminous flux and the second color partial luminous flux in different directions with each other or in a direction parallel to each other, a polarization change element which includes a polarization beam splitter array in which a plurality of polarization separation films and a plurality of reflective films are arranged alternately, and a polarization direction rotation element which is disposed either at a position where light transmitted through the polarization separation film is emitted or at a position where light reflected by the reflective film is emitted. The first color partial luminous flux incident on the polarization separation film is uniformed in a first polarization direction, and the second color partial luminous flux incident on the reflective film is uniformed in a second polarization direction. The invention can also include a transmission optical element which is disposed either at an incident side or at an emitting side of the polarization change element, and transmits an image formed by the luminous flux division optical element to an illuminated area, and a superposition optical element for superposing partial luminous flux emitted from the polarization change element at the illuminated area.
With this arrangement, first, the light from a light source is divided into a plurality of partial luminous fluxes and collected by the luminous flux division optical element, and each of the partial luminous fluxes is separated into the first color partial luminous flux and the second color partial luminous flux. The separated first color light and second color light enter the polarization change element having the polarization beam splitter array and the polarization direction rotation element, and are transformed into the first color partial luminous flux and second color partial luminous flux, each luminous flux having desired polarization state for each color light. Here, the polarization beam splitter array has a structure in which a plurality of pairs of polarization separation film and reflective film are arranged, and the polarization direction rotation elements are disposed at the emitting side of the polarization beam splitter array by selecting the positions corresponding to the positions of the polarization separation films or those of the reflective films.
For example, the polarization direction rotation elements are disposed only at the emitting side of the polarization separation films. Accordingly, of the first color partial luminous flux and the second color partial luminous flux, one enters a polarization separation film, and the other enters a reflective film selectively. Furthermore, the first color partial luminous flux and second color partial luminous flux are individually separated at the polarization beam splitter array into two kinds of polarization luminous fluxes, that is, a partial luminous flux having the first polarization direction which allows transmission of the polarization separation film and a partial luminous flux having the second polarization direction which is reflected by the polarization separation film.
Of the two kinds of polarization luminous fluxes, the polarization direction of one of the polarization luminous fluxes is rotated about 90xc2x0 by passing through a retardation film (polarization direction rotation element) such as a xcex/2 wavelength plate. Since the first color partial luminous flux and the second color partial luminous flux enter different films (polarization separation film and reflective film), respectively, the first color partial luminous flux and the second color partial luminous flux are uniformed in different polarization directions such that the first color partial luminous flux is uniformed in a first polarization direction and the second color partial luminous flux is uniformed in a second polarization direction.
For example, every first color partial luminous flux is arranged in S polarization light and every second color partial luminous flux is arranged in P polarization light. Then these partial luminous fluxes are superposed at the illuminated area through the superposition optical element. The transmission optical element has a function to transmit each partial luminous flux to the illuminated area The transmission optical element can be disposed either at the incident side or at the emitting side of the polarization change element. If the transmission optical element is disposed at the incident side of the polarization change element, each partial luminous flux becomes possible to enter the polarization change element at a predetermined angle, thereby making it easy to improve the polarization separation function of the polarization separation film. Thus, on the point of illumination efficiency, it is more advantageous to dispose the transmission optical element at the incident side of the polarization change element. On the other hand, if the transmission optical element is disposed at the emitting side of the polarization change element, it is possible to make one-piece optical element including the superposition optical element and the transmission optical element by implementing the function of the superposition optical element in the superposition optical element. It is therefore more advantageous to dispose the transmission optical element at the emitting side of the polarization change element when the number of parts needs to be reduced. As described above, according to the first aspect of the present invention, non-polarized light from a light source is transformed into polarization luminous flux which has a uniform polarization direction for each color light in advance. Thus, it is possible to reduce the polarization dependency of the optical elements, such as dichroic prisms and polarization beam splitters, which are disposed at more downstream side of the light path than the illumination optical system. It is therefore also possible to increase illumination efficiency.
Further, according to a second aspect of the present invention, there can be provided an illumination optical system including a color light separation optical element which separates the light from a light source into a first color light and a second color, light, and emits the first color light and the second color light in different directions with each other or in a direction parallel to each other, a luminous flux division optical element which divides the first color light into a plurality of the first color partial luminous flux, divides the second color light into a plurality of the second color partial luminous flux, and collects each of the partial luminous fluxes. The invention can further include a polarization change element which includes a polarization beam splitter array in which a plurality of polarization separation films and a plurality of reflective films are arranged alternately, and a polarization direction rotation element which is disposed either at a position where the light transmitted through the polarization separation film is emitted or at a position where the light reflected by the reflective film is emitted. The first color partial luminous flux incident on the polarization separation film is uniformed into polarized light having a first polarization direction, and the second color partial luminous flux incident on the reflective film is uniformed into polarized light having a second polarization direction. The invention can further include a transmission optical element which is disposed either at an incident side or at an emitting side of the polarization change element, and transmits an image formed by the luminous flux division optical element to an illuminated area, and a superposition optical element for superposing partial luminous flux emitted from the polarization change element at the illuminated area.
With this arrangement, first, the light from a light source is separated into the first color light and the second color light by the color light separation optical element. The first color light and the second color light are individually divided into a plurality of partial luminous fluxes and collected by the luminous flux division optical element. Specifically, the first color light is divided into the first color partial luminous fluxes, and the second color light is divided into the second color partial luminous fluxes. Each of these partial luminous fluxes enters the polarization change element having the polarization beam splitter array and the polarization direction rotation element, and is transformed into the first color partial luminous flux and second color partial luminous flux, each partial luminous flux having desired polarization state for each color light. Here the structure of the polarization beam splitter array is the same as that of the illumination optical system of the first aspect described above. Accordingly, of the first color partial luminous flux and the second color partial luminous flux, one enters into a polarization separation film, and the other enters into a reflective film. The subsequent operation is the same as that of the previous illumination optical system of the first aspect.
In the case of illumination optical system of the second aspect, non-polarized light from a light source is transformed into polarization luminous flux which has a uniform polarization direction for each color light in advance, thus it is possible to obtain the same effect as that of the first aspect. Furthermore, in the illumination optical system of the second aspect, since the color light separation optical element is disposed between the light, source and the luminous flux division optical system, highly parallel light can be entered into the color light separation optical element. Thus in the color light separation optical element, separation of color light can be performed much more efficiently without fail. In this regard, in the illumination optical system of the second aspect, as is the case with the illumination optical system of the first aspect, the transmission optical element can be disposed either at the incident side or at the emitting side of the polarization change element.
Furthermore, according to a third aspect of the present invention, there can be provided an illumination optical system including a luminous flux division optical element which divides light from a light source into a plurality of partial luminous fluxes and collects each of the partial luminous fluxes, a color light separation optical element which separates the each partial luminous flux into first color partial luminous flux and second color partial luminous flux, and emits the first color partial luminous flux and the second color partial luminous flux in different directions with each other or in a direction parallel to each other, and a polarization change element which includes a polarization beam splitter array in which a plurality of polarization separation films are arranged at a predetermined interval, and polarization direction rotation elements which are arranged at the predetermined interval and are disposed at an emitting side of the polarization beam splitter array. The first color partial luminous flux incident on an incident side end plane of the polarization separation film where the polarization direction rotation elements are not disposed at an emitting side of the film and transmitting through the polarization separation film, and the first color partial luminous flux reflected by the polarization separation film and then reflected by an adjacent polarization separation film once again and transmitting through the polarization direction rotation elements are uniformed in a first polarization direction to be emitted, while the second color partial luminous flux incident on an incident side end plane of the polarization separation film where the polarization direction rotation elements are disposed at an emitting side of the film and transmitting through the polarization separation film and then transmitting through the polarization direction rotation element, and the second color partial luminous flux reflected by the polarization separation film and then reflected by an adjacent polarization separation film once again are uniformed in a second polarization direction to be emitted. The invention can also include a transmission optical element which is disposed either at an incident side or at an emitting side of the polarization change element, and transmits an image formed by the luminous flux division optical element on an illuminated area, and a superposition optical element for superposing partial luminous flux emitted from the polarization change element at the illuminated area.
With this arrangement, first, the light from a light source is divided into a plurality of partial luminous fluxes and collected by the luminous flux division optical element, and each of the partial luminous fluxes is separated into the first color partial luminous flux and the second color partial luminous flux by the luminous flux division optical element. The separated first color light and second color light enter the polarization change element having the polarization beam splitter array and the polarization direction rotation element, and are transformed into the first color partial luminous flux and second color partial luminous flux, each partial luminous flux having desired polarization state for each color light. Here, the polarization beam splitter array has a structure in which a plurality of polarization separation films are arranged, and polarization direction rotation elements are disposed at the emitting side of the polarization beam splitter array by selecting the positions corresponding to the specific positions of the polarization separation films. For example, the polarization direction rotation elements are disposed only at the emitting side of every other polarization separation films. Now, suppose the polarization separation film which is provided with the polarization direction rotation element at the emitting side is referred to as a polarization separation film A, and the polarization separation film which is not provided with the polarization direction rotation element at the emitting side is referred to as a polarization separation film B for convenience sake. Accordingly, of the first color partial luminous flux and the second color partial luminous flux, one enters the polarization separation film B, and the other enters the polarization separation film A, selectively.
In the same manner as the polarization separation film described above, the polarization separation films A and B separate the entered partial luminous flux into partial luminous flux having the first polarization direction which allows transmission and partial luminous flux having the second polarization direction which is reflected. The partial luminous flux which has transmitted through the polarization separation film B is emitted from the polarization change element as the partial luminous flux having the first polarization direction. Also, the partial luminous flux which has been reflected by the polarization separation film B is the partial luminous flux having the second polarization direction, is reflected once again by the adjacent polarization separation film A, and then is rotated about 90xc2x0 by passing through a retardation film (polarization direction rotation element) such as a xcex/2 wavelength plate. Then the partial luminous flux is emitted from the polarization change element as the partial luminous flux having the first polarization direction. On the other hand, the partial luminous flux which has transmitted through the polarization separation film A is the partial luminous flux having the first polarization direction, is rotated about 90xc2x0 by passing through a retardation film such as a xcex/2 wavelength plate, and is emitted from the polarization change element as the partial luminous flux having the second polarization direction. Furthermore, the partial luminous flux which has been reflected by the polarization separation film A is reflected once again by the adjacent polarization separation film B, and then is emitted from the polarization change element as the partial luminous flux having the second polarization direction.
Since the first color partial luminous flux and the second color partial luminous flux enter the polarization separation film distinguished by the existence of the polarization direction rotation element, the first color partial luminous flux and the second color partial luminous flux are uniformed in different polarization directions such that the first color partial luminous flux is uniformed in a first polarization direction and the second color partial luminous flux is uniformed in a second polarization direction.
For example, the first color partial luminous fluxes are all arranged in S polarization light and the second color partial luminous fluxes are all arranged in P polarization light. Then these partial luminous fluxes are superposed at the illuminated area through the superposition optical element. The subsequent operation is the same as that of the previous illumination optical system of the first aspect.
In the illumination optical system of the third aspect, as compared with the illumination optical systems of the first aspect and the second aspect, of the first color partial luminous flux and second color partial luminous flux within the polarization change element, it is possible with ease to make the difference of the light path length smaller between the partial luminous flux having the shortest light path and the partial luminous flux having the longest light path. Thus, in the illuminated area, it is possible to make the magnification factor of the first color partial luminous flux and the magnification factor of the second color partial luminous flux the same. Consequently, illumination efficiency can be improved. Also, while the polarization beam splitter arrays in the above-described illumination optical systems of the first and second aspects have the polarization separation films and the reflective films, the polarization beam splitter array in the illumination optical system,of the third aspect has only the polarization separation films. Thus the structure of the polarization beam splitter array is simple, and it is therefore easy to be manufactured.
Moreover, according to a fourth aspect of the present invention, there can be provided an illumination optical system including a color light separation optical element which separates light from a light source into first color light and second color light, and emits the first color light and the second color light in different directions with each other or in a direction parallel to each other, a luminous flux division optical element which divides the first color light into a plurality of the first color luminous fluxes, divides the second color light into a plurality of the second color luminous fluxes, and collects each of the partial luminous fluxes, and a polarization change element which includes a polarization beam splitter array in which a plurality of polarization separation films are arranged at a predetermined interval, and a polarization direction rotation elements which are arranged at the predetermined interval and are disposed at an emitting side of the polarization beam splitter array. The first color partial luminous flux incident on an incident side end plane of the polarization separation film where the polarization direction rotation elements are not disposed at an emitting side of the film and transmitting through the polarization separation film, and the first color partial luminous flux reflected by the polarization separation film and then reflected by an adjacent polarization separation film once again and transmitting through the polarization direction rotation element are uniformed in a first polarization direction to be emitted, while the second color partial luminous flux incident on an incident side end plane of the polarization separation film where the polarization direction rotation element is disposed at an emitting side of the film and transmitting through the polarization separation film and then transmitting through the polarization direction rotation element, and the second color partial luminous flux reflected by the polarization separation film and then reflected by an adjacent polarization separation film once again are uniformed in a second polarization direction to be emitted. The invention can also include a transmission optical element which is disposed either at an incident side or at an emitting side of the polarization change element, and transmits an image formed by the luminous flux division optical element on an illuminated area, and a superposition optical element for superposing the partial luminous fluxes emitted from the polarization change element at the illuminated area.
With this arrangement, first, the light from a light source is separated into the first color light and the second color light by the color light separation optical element. The first color light and the second color light are individually divided into a plurality of partial luminous fluxes and collected by the luminous flux division optical element. Specifically, the first color light is divided into the first color partial luminous fluxes, and the second color light is divided into the second color partial luminous fluxes. Each of these partial luminous fluxes enters the polarization change element having the polarization beam splitter array and the polarization direction rotation element, and is transformed into the first color partial luminous flux and second color partial luminous flux, each partial luminous flux having desired polarization state for each color light. Here the structure of the polarization beam splitter array is the same as that of the illumination optical system of the third aspect described above. Accordingly, the first color partial luminous flux enters the polarization separation film B, and the second color partial luminous flux enters the polarization separation film A individually by selecting positions. The subsequent operation is the same as that of the illumination optical system of the third aspect.
In the illumination optical system of the fourth aspect, in the same manner as the illumination optical system of the third aspect, as compared with the illumination optical systems of the first aspect and the second aspect, of the first color partial luminous flux and second color partial luminous flux within the polarization change element, it is possible to make the light path length difference smaller between the partial luminous flux having the shortest light path and the partial luminous flux having the longest light path. Thus, in the illuminated area, it is easily possible to make the magnification factor of the first color partial luminous flux and the magnification factor of the second color partial luminous flux the same. Consequently, illumination efficiency can be improved. Also, in the same manner as the illumination optical system of the third aspect, the structure of the polarization beam splitter array is simple, thus it is easy to be manufactured.
The color light separation optical element to be used in the illumination optical system of the first, the second, the third, and the fourth aspects can be constructed of two mirrors, one optical part having two mirrors, a reflective hologram, or a transmissive hologram.
When constructing the color light separation optical element by two mirrors, the first mirror may be set to a dichroic mirror for performing color separation, and the second mirror may be set to perform a reflective mirror. In general, dichroic mirrors and reflective mirrors have high reflection factor. Thus if such mirrors are used in the structure, it becomes possible to separate a color light with high efficiency without fail. Here, it is possible to construct a reflective mirror not only using a general reflective mirror which is formed with metal film such as aluminum, but also using a dichroic mirror which reflects specific color light. With this arrangement, unnecessary light (for example, infrared light ultraviolet light, and specific color light such as yellow light) can be removed from the illumination light by the color light separation optical element. Thus when using these illumination optical systems for a projector, it is possible to improve the reliability of the light modulation device used for the projector, and to improve image quality of the projection image. In this regard, the function of the second mirror is to reflect a specific color light which is transmitted through the first mirror, thus the second mirror is not necessarily a dichroic mirror. However, when using a dichroic mirror, it is easy to obtain higher reflection factor as compared with a general reflective mirror, and thus it is convenient to increase light utilization efficiency in the color light separation optical element.
Furthermore, when using two mirrors, it is preferable to dispose the first mirror and the second mirror as follows:
(1) The first mirror and the second mirror are not parallel to each other, the first mirror is disposed at an angle of 45xc2x0 to the optical axis of the light source, and the second mirror is disposed at an angle of (45+xcex1)xc2x0 to the optical axis of the light source.
(2) The first mirror and the second mirror are not parallel to each other, the first mirror is disposed at an angle of (45+)xc2x0 to the optical axis of the light source, and the second mirror is disposed at the angle of 45xc2x0 to the optical axis of the light source.
(3) The first mirror and the second mirror are not parallel to each other, the first mirror is disposed at an angle of (45+xcex2)xc2x0 to the optical axis of the light source, and the second mirror is disposed at the angle of (45xe2x88x92xcex2)xc2x0 to the optical axis of the light source.
(4) The first mirror and the second mirror are parallel to each other at a predetermined distance, and are disposed at an angle of 45xc2x0 to the optical axis of the light source.
Particularly, when disposing the mirrors as in the cases (3) and (4), a color light can be separated symmetrically with respective to a predetermined axis, and thus it is preferable for simplifying the structure of the transmission optical element.
Also, in the above cases (1) to (3), the function of the color light separation optical element is to make the directions of the luminous fluxes which are emitted toward the polarization change element different between the first color partial luminous flux and the second color partial luminous flux. Thus in order to realize this function, the first mirror and the second mirror may be disposed not parallel to each other, and thus the disposition angles of the first mirror and the second mirror are not limited to the examples described above. However, the optical characteristic of the transmission optical element needs to be set appropriately in response to an incident angle of the color light to the transmission optical element.
Next, a description will be given of the case where the color light separation optical element is composed of an optical part having two mirrors. For an optical part having two mirrors, examples are as follows:
(A) An optical part including a plate translucent member, a dichroic mirror disposed on one of two planes opposed with each other of the translucent member, and a reflective mirror disposed on the other of the planes.
(B) An optical part including a plate translucent member, a rectangular prism fixed firmly on one of two planes opposed with each other of the translucent member, a reflective mirror disposed on the other of the planes, and a dichroic mirror disposed between the translucent member and the rectangular prism.
(C) An optical part including a plate translucent member, a plurality of small size rectangular prisms fixed firmly on one of two planes opposed with each other of the translucent member, a reflective mirror disposed on the other of the planes, and a dichroic mirror disposed between the translucent member and the rectangular prisms.
When the color light separation optical element is composed of one optical part like this, assembling the optical system can be made easily. Also, if one optical parts such as (B) or (C) is used, light enters the dichroic mirror through a rectangular prism having a refraction factor greater than 1. Thus the incident angle of the light on the dichroic mirror is narrowed, so that the light separation characteristic of the dichroic mirror is enhanced, and light path shift can be eliminated. Furthermore, if one optical part such as (C) is used, the prism part can be miniaturized, and thus the color light separation optical element can be miniaturized and the weight thereof can be saved. In this regard, it is possible to construct a reflective mirror not only using a general reflective mirror which is formed with metal film such as aluminum, but also using a dichroic mirror which reflects specific color light, and the above-described effect can be obtained. The function of the second mirror is to reflect a specific color light which has been transmitted through the first mirror, thus the second mirror is not necessarily a dichroic mirror. However, when using a dichroic mirror, it is easy to obtain a higher reflection factor as compared with a general reflective mirror, and thus it is convenient to increase light utilization efficiency in the color light separation optical element.
Furthermore, in the optical parts (A) to (C), one of the planes, on which a dichroic mirror is disposed and the other of the planes, on which a reflective mirror is disposed, are preferably arranged as follows:
(a) The one of the planes and the other of the planes are not parallel to each other, the one of the planes is disposed at an angle of 45xc2x0 to the optical axis of the light source, and the other of the planes is disposed at an angle of (45xe2x88x92xcex1)xc2x0 to the optical axis of the light source.
(b) The one of the planes and the other of the planes are not parallel to each other, the one of the planes is disposed at an angle of (45+xcex1)xc2x0 to the optical axis of the light source, and the other of the planes is disposed at an angle of 45xc2x0 to the optical axis of the light source.
(c) The one of the planes and the other of the planes are not parallel to each other, the one of the planes is disposed at an angle of (45+xcex2)xc2x0 to the optical axis of the light source, and the other of the planes is disposed at an angle of (45xe2x88x92xcex2)xc2x0 to the optical axis of the light source.
(d) The one of the planes and the other of the planes are parallel to each other with a predetermined distance therebetween, and are individually disposed at an angle of 45xc2x0 to the optical axis of the light source.
Particularly, when disposing the mirrors as in the cases (c) and (d), a color light can be separated symmetrically with respective to a predetermined axis, and thus it is preferable for simplifying the structure of the transmission optical element.
Also, in the above cases (1) to (3), the function of the color light separation optical element is to make the direction of the first color partial luminous flux different from that of the second color partial luminous flux which are emitted toward the polarization change element. Thus in order to realize this function, the one of the planes and the other of the planes may be disposed not parallel to each other, and thus the disposition angles of the one of the planes and the other of the planes are not limited to the examples described above. However, the optical characteristic of the transmission optical element needs to be set appropriately in response to an incident angle of the color light to the transmission optical element.
Finally, a description will be given of the case where the color light separation optical element is made of a reflective hologram element or a transmissive hologram element. In this case, the color light separation optical element can be constructed of one plate hologram, thus the number of parts of the color light separation optical element can be reduced and the illumination optical system can be miniaturized and the weight thereof can be saved.
The luminous flux division optical element to be used for an illumination optical system can be constructed of a lens array, a mirror array, a light guiding rod having four reflection planes, and so forth. If a mirror array is used, the cost becomes lower than the case of using a lens array or a light guiding rod. Also, if a mirror array or a light guiding rod is used, spherical aberration, which always accompanies with a lens array, does not occur. Thus light condensing is enhanced, and illumination efficiency can be improved.
Also, in the illumination optical system of the present invention, it is further preferable to dispose a dichroic filter array in order to block unnecessary incident color light on an incident side of the polarization beam splitter array. When disposing such a dichroic filter array, even if a color light separation optical element having a relatively higher incident angle dependency in light separation characteristic, unnecessary color light is prevented from entering into the polarization beam splitter array. Thus the first color light and the second color light can be separated without fail. In this regard, when disposing the transmission optical element at the incident side of the polarization change element, the dichroic filter array can be disposed not only between the transmission optical element and the polarization change element, but also at the incident side of the transmission optical element.
Furthermore, in the illumination optical system of the present invention, the color light separation optical element preferably has a color separation characteristic that green light is separated from red and blue light. With this arrangement, it becomes easy to optimize the selection characteristic of the green light of the color light separation optical element. Thus if a illumination optical system having such a structure is applied to a projector, it becomes easier to enhance the contrast and utilization efficiency of green light, and it becomes possible to display a projection image with high contrast and brightness.
Moreover, using the illumination optical system described above, when constructing a projector having a light modulating device for modulating the light emitted from the illumination optical system and a projection lens for projecting the modulated light by the light modulating device, it is possible to reduce the polarization dependency of the optical elements disposed at more downstream side of the light path than the illumination optical system. Thus it becomes possible to improve the image quality and brightness of the projection image.
Particularly, the illumination optical system of the present invention is preferably applied to the following projector:
(I) A projector including an illumination optical system described above, a first reflective light modulation device for modulating the first color light emitted from the illumination optical system, a second reflective light modulation device for modulating the third color light included in the second color light emitted from the illumination optical system, a third reflective light modulation device for modulating the fourth color light included in the second color light emitted from the illumination optical system, and a polarization beam splitter for separating light emitted from the illumination optical system into the first color light and the second color light. The projector can also include a projection lens which includes a color light separation/synthesis element for separating the second color light into the third color light and the fourth color light and also for synthesizing light emitted from the second reflective light modulation device and light emitted from the third reflective light modulation device to emit light to the polarization beam splitter, wherein light selected by the polarization beam splitter out of light emitted from the first reflective light modulation device and light emitted from the color light separation/synthesis element is projected.
(II) A projector including an illumination optical system described above, a first reflective light modulation device for modulating the first color light included in light emitted from the illumination optical system, a second reflective light modulation device for modulating the third color light included in the second color light emitted from the illumination optical system, a third reflective light modulation device for modulating the fourth color light included in the second color light emitted from the illumination optical system, first to fourth polarization beam splitters, a first wavelength selection retardation film disposed between the first polarization beam splitter and the third polarization beam splitter, and a second wavelength selection retardation film disposed between the third polarization beam splitter and the fourth polarization beam splitter. The projector can also include a projection lens for projecting light emitted from the fourth polarization beam splitter, wherein the first polarization beam splitter separates light emitted from the illumination optical system into a first color light and a second color light, the second polarization beam splitter leads the first color light separated by the first polarization beam splitter into the first reflective light modulation device, and also leads the first color light modulated by the first reflective light modulation device into the fourth polarization beam splitter, the first wavelength selection retardation film rotates about 90xc2x0 only a polarization direction of the third color light out of the third color light and the fourth color light included in the second color light separated by the first polarization beam splitter, the third polarization beam splitter leads the third color light and the fourth color light emitted from the first wavelength selection retardation film into the second reflective light modulation device and the third reflective light modulation device, and also leads the third color light and the fourth color light modulated by the second reflective light modulation device and the third reflective light modulation device into the second wavelength selection retardation film, the second wavelength selection retardation film rotates about 90xc2x0 only a polarization direction of the third color light out of the third color light and the fourth color light emitted from the third polarization beam splitter, and the fourth polarization beam splitter synthesizes the first color light emitted from the second polarization beam splitter, and the third color light and the fourth color light emitted from the second wavelength selection retardation film, and emits it toward the projection lens.
(III) A projector including an illumination optical system described above, a color separation optical system for separating light emitted from the illumination optical system into first color light, second color light, and third color light, a first transmissive light modulation device for modulating the first color light separated by the color separation optical system in response to an image signal, a second transmissive light modulation device for modulating the second color light separated by the color separation optical system in response to an image signal, a third transmissive light modulation device for modulating the third color light separated by the color separation optical system in response to an image signal, a color synthesis optical system for synthesizing the first color light, the second color light, and the third color light which have been modulated by the first transmissive light modulation device, the second transmissive light modulation device, and the third transmissive light modulation device, respectively, and a projection lens for projecting light synthesized by the color synthesis optical system.
When constructing a projector as described in (I), (II), and (III), the polarization dependency of the light separation characteristic of a dichroic mirror, a dichroic prism, and a polarization beam splitter array can be reduced. Thus, it is possible to achieve high quality and high brightness of the projection image, as well as cost reduction of the optical system which performs color light separation and synthesis. Also, in a projector having a structure as described in (II), each color light reaches the projection lens entirely through two polarization beam splitters, and thus the contrast of the projection image of the projector can be further enhanced. In this regard, the first and the fourth polarization beam splitters can be replaced with a dichroic mirror or a dichroic prism, and the cost reduction can be achieved in this case. Furthermore, in the illumination optical system of the present invention, of the three color lights, that is, the first color light, the second color light, and the third color light, one color light can be emitted with having a different polarization state from those of the other two color lights. Usually, in a so-called three-plate type projector, which includes three transmissive light modulation devices for modulating the first color light, the second color light, and the third color light, respectively, and the color synthesis optical system for synthesizing the first color light, the second color light, and the third color light, which have been modulated by the respective transmissive light modulation devices, in order to improve the synthesis efficiency of the color light in the color synthesis optical system, a xcex/2 wavelength plate is disposed just in front of or just at the back of the transmissive light modulation device. Accordingly, the polarization state of at least one color light of the incident light onto the color synthesis optical system differs from the polarization states of the other color lights. However, when using the illumination optical system of the present invention, the xcex/2 wavelength plate used for such a purpose can be omitted. Consequently, cost reduction can be achieved.
For example, when the illumination optical system has a structure in which green light is emitted as S polarization light, and blue and red light is emitted as P polarization light, it is unnecessary to dispose a xcex/2 wavelength plate just in front of or just at the back of the transmissive light modulation device. Also, when the illumination optical system has a structure in which green light is emitted as P polarization light, and blue and red light is emitted as S polarization light, the same number of xcex/2 wavelength plates becomes necessary for each transmissive light modulation device just in front of or just at the back of all, that is, the first to the third, transmissive light modulation devices. In a light path for each color, the same number of xcex/2 wavelength plates are disposed, thus chrominance non-uniformity can be reduced.
Furthermore, depending on the display characteristic of the transmissive light modulation device, the polarization state of the incident light onto the transmissive light modulation device may be limited. For example, when green light is entered as S polarization light, and blue and red light is entered as P polarization light into the transmissive light modulation device, the structure of the projector described in (III) is effective,

Illumination optical system and projector


In a branch device for multi-core optical fiber according to the present invention, a branch portion protector including a spindle-shaped protector and a perforated member which are integrally formed with each other is provided between the end portion of the multi-core optical fiber and the single-core optical fiber protection tubes so that no excessive force is exerted on the branching-out single-core optical fibers and the optical loss is stable.

FIGS. 1A and 1B show views for explaining an example of the branch portion of a conventional multi-core optical fiber tape. FIG. 1A illustrates the configuration of a multi-branch tube used to form the branch portion and FIG. 1B illustrates the configuration of the branch portion.
A multi-branch tube 31 is constituted by a optical fiber fixing portion 32 which receives and fixes a multi-core optical fiber tape 1, a plurality of single-core optical fiber protection tubes 33 which are disposed on the side opposite to the optical fiber fixing portion 32 so that branched single-core optical fibers 2 are passed therethrough respectively, and a branch portion accommodation space 34 which is formed between the optical fiber fixing portion 32 and the single-core optical fiber protection tubes 33, those portions 32, 33 and 34 being formed integrally with each other.
As shown in FIG. 1B, the multi-core optical fiber tape 1 is fixed at the vicinity of an end portion thereof in the optical fiber fixing portion 32 of the multi-branch tube 31, and the single-core optical fibers 2 branched from the optical fiber tape 1 are inserted through and protected by the single-core optical fiber protection tubes 33 of the multi-branch tube 31. Thus, the branch portion is formed.
FIGS. 2A and 2B show views for explaining another example of the branch portion of a conventional multi-core optical fiber tape. FIG. 2A illustrates the configuration of a multi-branch tube used to form the branch portion and FIG. 2B illustrates the configuration of the branch portion.
This example is different from the example of FIG. 1A in that a multi-branch tube 31 has no portion for fixing a multi-core optical fiber tape 1 and a protection tube 35 for protecting the multi-core optical fiber tape 1 is integrally formed. Accordingly, the optical fiber tape 1 inserted into the protection tube 35 is not fixed thereat.
The foregoing conventional branch portion of the multi-core optical fiber tape 1 is a result of contrivance as to a manner how to make the multi-core optical fiber tape 1 branch into plurality of the single-core optical fibers 2 not to be too extreme, and the branch portion is designed in consideration of the arrangement of the single-core optical fiber protection tubes 33 so that no force is exerted on the single-core optical fibers 2 in the respective single-core optical fiber protection tubes 33. The branch portion is however ineffective in protection of the branching out single-core optical fibers 2 in the branch portion accommodation space 34 between the end portion of the optical fiber tape 1 and the single-core optical fiber protection tubes 33.
There is therefore a problem in that when resin or the like is poured into the branch portion accommodation space 34 so as to fix the single-core optical fibers 2, force is exerted on the single-core optical fibers 2 to thereby cause increase of optical loss. Further, in the case there no resin is poured into the space 34, the increase of optical loss is similarly caused because of lack of stability of the optical fibers 2 in the branch portion accommodation space 34.

Branch device for multi-core optical fiber


An indoor unit includes a main body unit including a housing having an opening hole for pipe formed on a part of a side surface of the main body unit, a refrigerant pipe connection part projecting from inside to outside of the housing through the opening hole for pipe, and an attachment plate holding and fixing the refrigerant pipe connection part together with the housing to close the opening hole for pipe. The opening hole for pipe is formed over a first side surface on a side of the housing from which the refrigerant pipe connection part projects and a second side surface adjacent to the first side surface, and the attachment plate has an L shape including planes corresponding to the opening hole for pipe over the first side surface and the second side surface.

There has been known air-conditioning devices including refrigerant circuits to perform air-conditioning by using evaporation, condensation and other action of refrigerant. Among such air-conditioning devices, many ones are configured as a separate type, which includes, for example, an outdoor unit and an indoor unit and has a refrigerant circuit connecting the outdoor unit and the indoor unit by refrigerant pipes.
Here, the indoor unit includes a refrigerant pipe connection part projecting from a main body of the indoor unit to the outside. By causing the refrigerant pipe connection part to project to the outside, work to connect appliances in the indoor unit to outside refrigerant pipes can be done with ease. To cause the refrigerant pipe connection part to project to the outside, the refrigerant pipe connection part is brought to the outside through an opening hole for pipe formed on a part of a surface of a housing from the inside where the refrigerant pipe connection part is connected to the appliances. Then, an attachment plate is mounted onto the housing, and a part of the hole except for the refrigerant pipe connection part is covered with the attachment plate to close and seal the hole. By closing the hole with the attachment plate, leakage of air passing through the indoor unit from the parts other than an air outlet to the outside is prevented (for example, refer to Patent Literature 1).

Indoor unit and air-conditioning apparatus


The present invention relates to a polyethylene resin suitable for preparing moulded articles, such as caps and closures. The invention provides in particular a polyethylene resin comprising at least two polyethylene fractions A and B, wherein said polyethylene resin has a melt index (MI2), of at least 3.0 g/10 min to at most 5.5 g/10 min as measured according to ISO 1133, condition D, at 190° C. and under a load of 2.16 kg, and a density of at least 0.955 g/cm3 to at most 0.965 g/cm3 as measured according to ISO 1183 at 23° C., and a molecular weight distribution Mw/Mn which is at most 7.0, as determined by gel permeation chromatography, with Mw being the weight-average molecular weight and Mn being the number-average molecular weight; and wherein said polyethylene fraction A has a high load melt index (HLMI), as measured according to ISO 1133:1997 condition G at 190° C. and under a load of 21.6 kg, of at least 10.5 and a melt index (MI2) of at least 0.5 g/10 min to at most 1.5 g/10 min as measured according to ISO 1133, condition D, at 190° C. and under a load of 2.16 kg. The invention further relates to a process for preparing said polyethylene resin, to a cap or closure comprising said polyethylene, and to a process for producing such a cap or closure.

Caps and closures are widely used for various applications ranging from food and drink applications, such as for bottles containing carbonated or non-carbonated drinks, or for non-food applications such as containers for agrochemicals or chemicals (e.g. motor oil), cosmetics, or pharmaceuticals. Caps and closures are in general required to be strong enough to withstand the closure needs and soft enough to provide an excellent seal on the bottle or containers while not contributing to the taste or aroma of the bottle or container contents.
Polyethylene has become one of the materials of choice in the market of caps and closures because polyethylene offers a good balance of mechanical properties and can easily be processed either by injection moulding or by compression moulding. Important requirements for such polyethylene resin to be applied in the manufacture of caps and closures include appropriate rheological properties (processing ease), mechanical properties such as stiffness and environmental stress crack resistance (ESCR), and organoleptic properties, requirements which preferably need to be satisfied all at the same time.
It is for instance important that such polyethylene resin has the appropriate rheological properties, i.e. a flowability within certain limits to ensure that the final product properties are desirable. For example, the flowability of the polyethylene resin must be sufficiently high to enable it to flow to all areas of the mould when injected so as to form the desired cap or closure. Also, the higher the flow rate of the polyethylene melt, the greater the speed at which it can be injected into the mould and the shorter the processing time, which improves productivity.
In applications where caps and closures may be in contact with aggressive food and non-food media and/or subject to external stress, a sufficiently high stress crack resistance is of particular importance.
Furthermore, especially with regard to the food applications of caps and closures, it is important that the polyethylene has good taste and odor properties and low levels of extractables that can migrate into the food.
Moreover, recent efforts to reduce the weight of the polyethylene caps and closures have created a further need in the industry to develop polyethylene resins for caps and closures having even higher stress cracking resistance. Currently available resins have a reasonable high stress crack resistance, but they leave room for improvement.
Typically, polyethylene resins with higher densities and higher melt index have been applied in the art for producing caps and closures. Such resins, while having good processability and delivering articles with good organoleptic properties, leave room for improvement, since they generally provide a poorer ESCR, which may cause the formation of cracks around the injection point or at the edges of the caps or closures. In consequence, such resins present limitations for designing caps and closures that have superior ESCR requirements, such as caps for carbonated drinks or light-weight caps, as indicated above.
On the other hand, using polyethylene resins with lower densities and/or lower melt index for preparing caps and closures provides improved ESCR properties, but this is usually at the detriment of rheological and processing properties of the resins. The use of such type of resins may therefore lead to constrains in terms of mould shelf life, processing and cap functionality. Process modifications are needed for producing caps and closures from such type of resins, such as an increase in temperature due to a lower viscosity of the resin, as well as an increase of the clamping force of a mould during processing, which results in more mould wear. Also, due to the lower resin stiffness, caps or closures produced with such type of resins are softer and tend to show a higher bridge breaking force.
Therefore, in view of the above, there remains an ongoing need to develop caps and closures that display improved ESCR. Accordingly, there also remains an ongoing need to develop polyethylene resins for producing such caps and closures. However, such improved ESCR properties should not be at the cost of worsening other properties of the resins, or the caps or closures made therefrom. In particular, there remains an ongoing need to improve the ESCR of polyethylene resins for caps or closures without deterioration of processability, and other mechanical and organoleptic properties of the resins and caps or closures made therefrom.
Accordingly, it is an object of the present invention to provide a polyethylene resin and a cap or closure made therefrom having improved ESCR.
It is also an object of the present invention to provide a polyethylene resin and a cap or closure made therefrom having acceptable mechanical properties, such as e.g. stiffness.
It is also an object of the present invention to provide a polyethylene resin and a cap or closure made therefrom having acceptable organoleptic properties.
It is also an object of the present invention to provide a polyethylene resin and a cap or closure made therefrom having improved ESCR without deterioration of their other properties such as mechanical and organoleptic properties.
It is an additional object of the present invention to provide a polyethylene resin and a cap or closure made therefrom, having improved ESCR, while at the same time having acceptable or even improved processability. Yet another object of the invention is also to reduce mould wear and/or to increase the shelf life of the mould used for producing caps or closures.

Polyethylene resin and caps or closures made therefrom


A portable electrochemical power supply for handheld electronic devices, such as cellular telephones, is disclosed. The power supply includes a housing with an electrical connector, a circuit board, and a removable electrochemical cell disposed therein. The circuit board carries power supply circuitry which receives electrical energy from the electrochemical cell and provides a power supply output for powering an external device.

This invention generally relates to a portable direct current power supply for a handheld electronic device. More particularly, this invention pertains to a direct current power supply for devices such as cellular phones.
The proliferation of portable battery powered devices, such as cellular telephones, has increased dramatically in the last several years and this trend is expected to continue. The phones typically use a rechargeable battery that is built into the phone to provide the needed power. The length of time that the battery powers the phone is dependent primarily upon the size of the battery and the number of energy consuming features built into the phone. In response to consumer demand, cell phone manufacturers incorporate into the phones features such as the ability to send and receive digital pictures and/or text messages. Unfortunately, the inclusion of these features usually places additional demands on the rechargeable batteries that power the cell phones. The net result is that the cell phones' run times become shorter and shorter due to the increased power demands. At the same time that the electrical demand placed on the battery is increasing, the size and weight of cell phones is decreasing in order to reduce the size of the phones. As the size of the cell phone is reduced, the size of the battery compartment built into the cell phone is also reduced. The existence of these two trends (i.e. increased electrical demand and reduced battery size) has caused many cell phone users to experience a failed telephone call or data transmission due to the depletion of their phone's battery at an inopportune moment. An additional trend that complicates resolving this problem is that most cell phones require a battery that has specific size and shape characteristics. In order to encourage consumers to purchase replacement batteries from the cell phone manufacturer, the cell phones are made with batteries that have unique shapes, locking mechanisms, voltage requirements, etc. Furthermore, the recharging port built into the cell phones limit the type of charger that can be connected to the cell phone. Collectively, these factors limit the consumer's ability to rapidly replace the depleted battery with another power supply.
Numerous attempts have been made to develop a suitable portable power supply for cellular telephones. For example, U.S. Pat. No. 6,127,801 discloses a power supply that includes a battery pack and a base unit which has bidirectional circuitry. The battery pack is made to snap into the base unit which is designed to be clipped onto the cellular telephone. Unfortunately, the battery pack and base unit tend to increase the size and weight of the cell phone, which is contrary to the consumer's desire, while also causing additional proliferation in the number of components the consumer needs to replace when the phone's battery is depleted. In another example, U.S. Pat. No. 6,709,784 discloses a unique battery pack that can be plugged into a cellular phone's contact to recharge the phone's built-in rechargeable battery and/or directly power the cell phone. This invention bundles the battery with the plug that allows the battery pack to be connected to the phone. Consequently, when the battery pack's battery is depleted the entire battery pack, including the plug, must be discarded which increases the consumer's cost.
Therefore, there exists a need for a portable direct current power supply that uses a commonly available battery that the consumer can readily insert into and remove from a reusable housing. The power supply needs to be lightweight, volume efficient and easily adaptable to a wide array of cell phones that utilize batteries of various shapes and sizes.


Legacy automatic variable capacitor KVAR compensation systems typically use either electromechanical devices such as relays or contactors of various forms and types to switch the selected capacitors in and out of the electrical system under some form of electronic control. These systems are slow and discontinuous in their ability to closely regulate the exact value of compensatory capacitance needed to compensate the variable and rapidly changing reactive power KVAR in the electrical power transmission and distribution networks. The present invention provides a fast response active KVAR compensator based on a variable transimpedance topology.

In AC electrical power distribution networks, the optimized operating conditions for maximum energy efficiency in the usage, transmission, and delivery of AC electrical power is when the voltage and the current are closely in phase, and the reactive power (KVAR) is close to zero. However, with the addition of reactive loads and inherent reactive components such as capacitance and inductance in the transmission and distribution system, the AC current in the system can be phase-shifted with respect to the voltage waveform. This creates power quality issues that affect the efficient transmission and usage of the delivered electrical power. The degradation in power quality due to the increasing reactive power value is measured by the amount of phase angle shift of the current behind (lagging) or ahead (leading) with respect to the voltage waveform. Reactive power value is derived by the following equation.KVAR=√{square root over (KVA2−KW2)}  (1)where KVAR is the total reactive power, KVA is the total apparent power, and KW is real power.
Noted that only the real power KW is useful for productive consumption, whereas the reactive power KVAR is wasted power. But since the total apparent power KVA is made up of KW and KVAR as per the equation above, both power components are be generated, transmitted, and delivered. As such, an increasing phase shift of the AC current with respect to the voltage waveform, which means increasing value of reactive power KVAR will translate into a significant efficiency decrease in the electrical power system.
This problem is well known and there are various legacy methods of compensating and removing reactive power KVAR by introducing reactive components at various points within the electrical system. Typically these are capacitors introduced in shunt across the electricity supply lines to cancel the generally lagging current due to magnetic elements such as electric motors, fluorescent ballasts, transformers, etc.
This has been traditionally achieved by adding fixed and variable capacitor banks in shunt across the electrical power transmission and distribution system. If a known and reproducible KVAR problem is stable, then a fixed capacitor KVAR compensation bank can be permanently installed at the point to be compensated. If the reactive power KVAR is changing, then automatic variable capacitor banks that can respond, under electronic controls and KVAR sensing, and switch in the amount of capacitance needed to compensate for the level of KVAR at any given time.
These legacy automatic variable capacitor KVAR compensation systems typically use either electromechanical devices such as relays or contactors of various forms and types to switch the selected capacitors in and out of the electrical system under some form of electronic control. In more recent versions of KVAR compensation systems, semiconductor switching devices, such as triodes for alternating current (TRIACs) and silicon-controlled rectifiers (SCRs), and electromechanical switching devices have been seen in use.
Because of the need to switch discrete component capacitors in and out of circuit by various switching means, these legacy reactive power KVAR compensators are slow and discontinuous in their ability to closely regulate the exact value of compensatory capacitance needed to compensate the variable and rapidly changing reactive power KVAR in the electrical power transmission and distribution networks.

Fast response active reactive power (KVAR) compensator