The object of the present invention is to provide an optical device which has obliterated, by the use of a nonlinear optical crystal, the need for a complicated adjustment operation of positions as seen in an optical device used for obtaining an output light having a frequency different from an input light. To be specific, Q switching electrodes 12A, 12B, phase adjustment electrodes 9A, 9B and periodic domain inversion part 15 are disposed in desired parts of path 2 in an optical crystal 1 having nonlinear optical character, electro-optical character and laser activity. By the action of an input light P0 supplied from an input side 3, oscillation light P1 is oscillated, harmonic is generated by nonlinear optical character and periodic domain inversion part 15, or output light P2 having a frequency different from that of input light P0 is emitted from output side 4 by optical parametric oscillation. As a result of changes in voltage between phase adjustment electrodes 9A, 9B, the refractive index of the corresponding part of the nonlinear crystal 1 is changed to adjust the oscillation frequency by to total length Lt of path 2. By changing voltage between Q switching electrodes 12A, 12B, a refractive index of slanting intersection of oblique side G of electrode 12A and path 2 can be changed to effect Q switching of oscillation light P1.

In this invention, each term means the following.
[Explanation of terms]
Period
In general, the term "period" inherently means a dimension of time. In this invention, however, it also means a dimension of length in a path through which a predetermined light passes inside an optical crystal.
Frequency
While the light is generally expressed by "wavelength", it is expressed by "frequency" in this invention. The "wavelength" corresponding to this "frequency" varies depending on the material of transmission path, as in the case of radio waves.
Optical Parametric Oscillation
This means a phenomenon wherein two frequencies .omega..sub.s and .omega..sub.i are generated by excitation of quadratic polarization with a light wave having a frequency .omega..sub.p. The relation of these frequencies is as expressed by the formula: EQU .omega..sub.p =.omega..sub.s +.omega..sub.i.
Domain
A region wherein polarization in ferroelectrics occurs in the same direction. The references relevant to this invention include the following.
[References]
Reference 1
P. A. Franken, A. E. Hill, C. W. Peters, G. Weinreich, "Generation of optical harmonics", Phys. Rev. Lett., 7, 118/1961.
Reference 2
J. A. Armstrong, N. Bleombergen, J. Ducuing and P. S. Pershen, "Interaction between light waves in a nonlinear dielectric", Phys. Rev., 127, No. 6, 1918/1962.
Reference 3
Eikai Cho, Hiromasa Ito and Fumio Inaba, 49.sup.th Applied Physics Convention, "Experiment of nonlinear light waveguide having domain inversion structure", 7a-ZD-9/1988.
Reference 4
E. J. Lim, M. M. Fejer, R. L. Byer, and W. J. Kozlovsky, "Blue light generation by frequency doubling in periodically poled lithium niobate channel waveguide", Electron. Lett., 25, 731/1989.
Reference 5
J. Webjorn, F. Laurell, and G. Arvidsson, "Blue light generated by frequency doubling of laser diode light in a lithium niobate channel waveguide", IEEE Photon. Tech. Lett., 1, 316/1989.
Reference 6
M. Yamada, N. Nada, M. Saitoh, and K Watanabe, "First-order quasi-phase matched LiNbO.sub.3 waveguide periodically poled by applying an external field for efficient blue second-harmonic generation", Appl. Phys. Lett., 62, 435/1993).
Reference 7
Y. Yamamoto, S. Yamaguchi, K. Suzuki, and N. Yamada, "Second-harmonic generation in a waveguide with domain-inverted regions like periodic lens sequence on z-face KTiOPO.sub.4 crystal", Appl. phys. Lett., 65, 938/1994.
Reference 8
Toshiaki Saihara, Masatoshi Fujimura and Hiroshi Nishihara, "Waveguide type SHG element by quasi-phase matching", Journal of Electron Information Communication Convention, 76,597/1993.
Reference 9
S. Miyazawa, "Ferroelectric domain inversion in Ti-diffused LiNbO.sub.3 optical waveguide", J. Appl. Phys., 50, 4599/1979.
Reference 10
H. Ito, C. Takyu, and H. Inaba, "Fabrication of periodic domain grating in LiNbO.sub.3 by electron beam writing for the application of nonlinear optical processes", Electron. Lett., 27, 1221/1991.
Reference 11
Motoki Ohashi, Choichi Takyu and Koichi Taniguchi, "Studies of periodic domain inversion structure of ferroelectric nonlinear optical crystal by electron beam writing", Journal of Electron Information Communication Convention Papers, C-I, J77-C-I, 383/1994.
Reference 12
S. Kurimura, M. Miura, and I. Sawaki, "New method of 20 mm-deep and 3.6 mm-periodic domain inversion for lst-order quasi-phase matching SHG in LiTaO.sub.3 waveguides", Conf. on Lasers and Electro-Optics, CPD5/1992.
Reference 13
Manabu Sato, Motoki Ohashi, Abedin Kaji Sarwar, Choichi Takyu and Masahiro Ito, "Bulk LiTaO.sub.3 Domain Inversion Lattice by Electric Field Application Method", Journal of Electron Information Communication Convention Papers, C-I, 366, J78-C-I, August/1995.
Reference 14
K S. Abedin, M. Sato, H. Ito, T. Maeda, K. Shimamura, and T. Fukuda, "Ordinary and extraordinary continuous wave lasing at 1.092 .mu.m and 1.082 .mu.m in bulk Nd: LiTaO.sub.3 crystal", J. Appl. Phys., 78,691, July/1995.
Reference 15
A. YARIV et al., OPTICAL WAVES IN CRYSTALS, pp.512-515, Table 12.2, WILEY-INTERSCIENCE, 1983.
Reference 16
Electric Communication Handbook, Ed. 25, First Division, 3.multidot.2, "Q switch", Ohm Corp., March, 1979.
[Developmental history of optical device]
Subsequent to the invention of the laser, a technique for generating a second harmonic at 347 nm by ruby laser beam (694 nm) irradiation of rock crystal was disclosed in Reference 1.
Since then, nonlinear optics have been remarkably developed and have become an object of scientific studies, as well as a practical device technique in significant progress.
The development of light wave technique, as in the case of the development of radio wave technique, requires a light source having any wavelength, namely, a light source having any frequency. However, the wavelength of oscillation by laser is principally a specific wavelength determined by the material having a laser activity. Therefore, generation of a light having an optional wavelength, which cannot be obtained directly using a laser, is desired. As a technique for this end, a technique using a material having nonlinear optical character, namely, a nonlinear optical material, has been noticeably developed in recent years.
For an efficient generation of coherent light waves having different wavelengths by the use of a nonlinear optical material, namely, a material having nonlinear optical effect (to be referred to as nonlinear optical character in this invention), it is necessary to realize matching between the velocity at which a new wavelength component, namely, a frequency component, created by mixing plural light waves is polarized, and the transmission velocity of the light wave emitted by the polarization. The matching of the velocities is called phase matching and is generally achieved by the use of a crystal having a birefingence property.
There is a method to achieve phase matching without relying solely on the birefringence property, that is, a method free of limitations in conventional phase matching, and such phase matching method is called a quasi-phase matching. According to this method, the maximum value of a nonlinear optical coefficient component, namely, a nonlinear optical tensor component, can be utilized. The tensor component is disclosed in Reference 15. While the principle proposition of quasi-phase matching appears in Reference 2, due to the difficulty in rotating the optic axis z of a crystal (hereinafter "optical axis z") periodically and precisely by 180.degree. on a .mu.m order, no specific device has been realized.
The inventor of this invention has disclosed, in Reference 3, a method for quasi-phase matching by a structure capable of periodic domain inversion by diffusion of impurities at periodic intervals on the surface of a material having ferroelectricity due to LiNbO.sub.3 (lithium niobate), namely, a ferroelectric crystal. This periodic domain inversion structure can be manufactured by planar processing alone which is similar to that applied to a semiconductor device, and this structure achieves generation of second harmonic of a near infrared ray. Nearly at the time when the above-mentioned Reference 3 reported the technique, similar techniques were disclosed in Reference 4 and Reference 5, and improvements of these techniques were disclosed in References 6-8.
Moreover, the inventor of this invention has disclosed, in References 10, 11 and 13, a technique affording, with regard to a ferroelectric crystal, domain control with precision on a micron order, of a domain inversion structure over the entire substrate, namely, the entire crystal, by an electric means, which domain inversion structure having been made to permit quasi-phase matching by utilizing a nonlinear optical coefficient in a more ensured manner. Specifically, this technique has realized a second harmonic generation at an efficiency near a theoretical value, by forming a periodic domain inversion part of not more than 10 .mu.m in a z board of LiTaO.sub.3 (lithium tantalate) having a thickness of 500 .mu.m, namely, a crystal board having the optical axis z direction set as in FIG. 19.
In addition, a structure generating millimeter wave to submillimeter wave having frequency .omega..sub.3, which is the difference in light wave between two different frequencies .omega..sub.1 and .omega..sub.2, via quasi-phase matching, as shown in FIG. 18, has been disclosed in Japanese Patent Unexamined Publication No. 6-110095. The "nonlinear optical crystal wherein nonlinear optical coefficient is periodically inverted" in the above-mentioned Japanese Patent Unexamined Publication No. 6-110095 and the periodic domain inversion part in this invention have substantially the same construction.
[quasi-phase matching]
The principle of the generation of harmonic by quasi-phase matching is explained in the following.
In general terms, nonlinear interactions between different wavelengths require phase matching to preserve momentum and to preserve energy. When such a requirement is not fulfilled, a nonlinear polarization wave induced in a substance by incident light wave and the light wave emitted by this nonlinear polarization wave interfere with each other to cancel each other, thus resulting in a failure to achieve effective conversion of frequencies.
In a second harmonic generation (hereinafter SHG), as shown in FIG. 10(c), harmonic output includes constant maximum level and minimum level repeats at an extremely weak intensity, in every interference distance calculated by the following formula, namely, length of coherence, Lc. ##EQU1##
wherein .lambda. is a wavelength, n is a refractive index, an inferior subscript F is a fundamental wave, and SH means harmonic component. Therefore, once the +/- symbols of the polarization wave generated every coherence length, Lc, can be alternately inverted by some means, the harmonic output can be effectively overlapped over the entire part subjected to the alternate inversion. In other words, by setting the period of domain inversion, namely, the domain period T, to twice the length of coherence, Lc, namely, 2Lc, the diffusion inside the nonlinear optical crystal can be cancelled to simulate phase matching, as shown in FIG. 10, part (a).
The stimulatory phase matching in this way is called quasi-phase matching (hereinafter to be referred to as QPM. A nonlinear optical material having a great tensor component but optically isotropic, or incapable of phase matching due to too great a dispersion, can be subjected to phase matching by this quasi-phase matching, thereby enabling utilization of such nonlinear optical material for SHG.
When the domain period T is set to thrice the length of coherence, Lc, namely, 3Lc, the outcome will be as shown in FIG. 10, part (b). The conditions to be fulfilled to perform QPM are generally expressed by the following formula: ##EQU2##
wherein m is a positive integer of 1, 2, 3 . . . and is an order of domain period T. In FIG. 10, (a) is the case where T=Lc, m=1; (b) is the case where T=3Lc, m=3; and (c) is the case where such domain period is not set, namely, phase mismatch.
When using a material dimensionally controlled to effect inversion as exemplified by periodic inversion of nonlinear optical coefficient d into +d and -d, the dimensional distribution of this nonlinear coefficient is subjected to Fourier expansion to determine the effective nonlinear optical coefficient.
In this case, when the ratio of the width of the part wherein z axis is substantially inverted about the z axis of the crystal substrate, to domain period T, namely, the ratio of the inverted width t to the domain period T in FIG. 14, which is called a duty ratio, is expressed by .xi. (0.ltoreq..xi..ltoreq.1), the maximum efficiency of QPM can be achieved when m=1 and .xi.=0.5. At a higher order action, the highest efficiency can be achieved when m=2 and .xi.=0.25. Accordingly, for a highly efficient quasi-phase matching, the control of the duty ratio .xi. is essential.
On the other hand, a nonlinear optical material is requested to have a broad pass band and a large nonlinear optical coefficient d, since it is used in the wavelength band where it is transmitted, namely, transmission frequency band. The relationship between the cut-off point of pass band at short wavelength side, i.e., high frequency side, of each optical material, and a relative property index d.sup.2 /n.sup.3 is as shown in FIG. 11.
In this quasi-phase matching, therefore, an optical material having a greater nonlinear optical coefficient d can be used under the optimal operative conditions free of limitations imposed on conventional phase matching. As shown in FIG. 11, LiNbO.sub.3 (QPM) and LiTaO.sub.3 (QPM) by QPM show properties superior to that of LiNbO.sub.3 and LiTaO.sub.3 without QPM.
A material having such a nonlinear optical character is required to be highly efficient. In addition, for a greater output to be achieved, the input should be also great, and such great input may destroy the nonlinear optical material. Thus, this material is suitable for a nonlinear optical interaction at low and medium output levels.
The relation between a transmission wavelength range of each typical optical crystal suitable for QPM and a nonlinear optical coefficient, namely, tensor components d.sub.33, d.sub.31 is shown in FIG. 17, and the use of tensor component d.sub.33 results in better QPM than the use of other tensor components such as tensor component d.sub.31.
However, since the tensor component d.sub.33 is usable when all electric fields to be interacted are parallel to the optical axis z of an optical crystal, it cannot be used at all in an interaction using conventional birefringence.
In other words, according to the QPM, LiNbO.sub.3 crystal, for example, permits effective use of the value of -40 pm/V of tensor component d.sub.33, which is about 7 times greater than that of the conventional tensor component d.sub.31, which is -6 pm/V. Thus, the QPM enables the use of a nonlinear optical coefficient which is about 7 times greater than the conventional one. As shown in FIG. 17, it is one of the materials having the greatest nonlinear character in the wavelength range of not more than wavelength 0.4 .mu.m.
[periodic domain inversion structure]
For periodic inversion of poling direction in a crystal as shown by the symbols of the polarized waves in FIG. 18, the +/- symbols of nonlinear optical coefficients need only be reversed. Therefore, a method for reversing the optical axis, namely, z axis, inside the optical crystal can be used. Such inversion of the z axis is called domain inversion in this invention. When the ferroelectric is a crystal of LiNbO.sub.3 or LiTaO.sub.3, a structure wherein the ferroelectric domains are alternately inverted by 180.degree. at certain periods, namely, a periodic domain inversion part 15, need only be formed.
Reference 9 and others disclose that, particularly in +z plane, namely, a plane orthogonal to the optical axis z of a crystal and disposed on the plus direction side of the z axis, the domain inversion occurs by internal factors such as impurities and distortion, and external factors such as heat and electric field. Such inversion is considered to be mainly caused by lowered Curie temperature in the part where impurities are dispersed. Therefore, when a domain inversion structure is manufactured by surface processing based on the dispersion of the impurities, namely, by processing from the surface of the crystal, while positively utilizing this major cause, the degree of freedom in structural development of the device can be markedly increased as compared to the manufacture method employed to form domain inversion structure having an optional shape, along with conventional crystal pulling.
Reference 3--Reference 5 disclose a technique of such domain control of a nonlinear optical material by processing from the surface. However, the domain inversion based on the diffusion of Ti (titanium) carried out in early stages was associated with disadvantages in that, since changes in refractive index were always observed, it was susceptible to diffraction and dispersion, and that treatment at high temperatures was necessary.
In order to overcome this inconvenience, the inventor of this invention performed periodic inversion of domain only with electron beam and electric field at room temperature, in an attempt to realize a periodic domain inversion structure without variations in refractive index, and disclosed, in Reference 10, a method for causing domain inversion by electron beam irradiation alone without application of heat or electric field.
This method comprises deposition of a metal such as chromium on the +z plane of LiNbO.sub.3 substrate and exposure, to electron beam, of the part on the -z plane without deposition, namely, the plane opposite from the +z plane, where domain inversion is desired, whereby a desired pattern is drawn thereon to give a periodic domain inversion structure.
The electron beam is hit using a modified scanning electronmicroscope. For example, when a domain inversion at a period of 7.5 .mu.m is desired on a z board (500 .mu.m thick) as a substrate, entire process scanning is performed at accelerating voltage of 25 kV, a dose of 2.times.10.sup.9 electrons/sec at zero DC bias at room temperature. According to the conventional method, a DC voltage needs to be applied to the both sides of a z board having an elevated temperature. This method obliterates such operation.
The surface of LiNbO.sub.3 having a domain inversion structure formed by periodic domain inversion by the above-mentioned electron beam irradiation was etched and observed by an optical microscopy. As a result, as shown in [-z plane microscopic photograph] and [+z plane microscopic photograph] of FIG. 12, domain inversion by electron beam irradiation was successively performed not only on the -z plane on the electron beam irradiation side but also to the +z plane on the rear side, and y plane, namely, a plane orthogonal with the mechanical axis y of the crystal, after cutting, polishing, etching and similar observation, showed extremely regular formation of main inversion layers from -z plane to +z plane. Here, the relation of electron beam irradiation and each plane of the optical crystal is as shown in FIG. 19.
The process of domain inversion formation is considered to be such that accelerated electron beam advances to the depth of only 1-2 .mu.m from the crystal surface to charge only locally, and at the vicinity of the surface, binding of atoms is loosened due to the injection impact of electrons to cause easy movement of the atoms, which leads to dislocation of Li (lithium) ions now easily mobile in local electric field and inversion of spontaneous polarization, which inversion once caused at a certain part is repeated in the z axis direction of the created electric field to ultimately reach +z plane on the rear surface.
However, the domain inversion by the above-mentioned electron beam tends to be associated with the difficulty in forming a successive dean shape. This is caused by a slight imbalance between the electric charge accumulated on the insulated part and the electric charge from spontaneous inversion of the substrate, wherein the charges are not completely offset but remain. This inconvenience is disclosed in Reference 11.
On the other hand, a potential domain control by direct electric field is expected and a method of domain inversion by direct application of electric field to a ferroelectric via stripe-patterned electrodes has been studied. Reference 6 discloses domain inversion of LiNbO.sub.3 by the application of pulse electric field at around room temperature, and Reference 12 discloses domain inversion of LiTaO.sub.3 by the application of electric field. In these methods involving application of electric fields, the voltage to be applied should be strictly controlled, since the voltage is near dielectric breakdown voltage of crystal.
Thus, the inventor of this invention has disclosed, in Reference 13, a method for forming a bulk domain inversion lattice wherein periodic domain inversion is performed not only on the surface of a nonlinear optical LiTaO.sub.3 crystal but also in mostly the entire thickness direction of the optical crystal by the application of electric field.
According to this method, for example, a LiTaO.sub.3 z board (500 .mu.m thick) as a substrate, which is a plate crystal having a surface plane and a bottom plane both orthogonal to optical axis z, is used Using the plane on the plus side of optical axis z as +z plane and that on the minus side as -z plane, a certain pattern is formed on the +z plane, namely, Al (aluminum) electrode having a stripe pattern formed by periodic domain inversion is deposited on the +z plane in a certain pattern, and Al electrode is uniformly deposited on the entirety of -z plane. The substrate is set in a vacuum chamber, and a direct voltage is applied between the electrodes on both sides. The stripe patterned electrode has a length of 4 mm, and three periods of 7.5 .mu.m, 7.8 .mu.m and 8.1 .mu.m are formed simultaneously at different positions on the same substrate.
The time-course changes in the applied voltage and inversion current were, as shown in FIG. 13, that the applied voltage was increased at ca. 2.5 kV/10 sec; domain inversion current was 10.4 kV, which means that it began to flow from the vicinity of the voltage corresponding to 20.8 kv/mm; when the applied voltage was maintained at a constant value of ca. 10.5 kV, the inversion current reached the maximum value of ca. 750 nA after a certain period of time, at which level the domain inversion occurred in the patterned part; and about 1 minute later, the current stopped automatically. The applied voltage from which inversion current began to flow matched with the anti-electric field voltage of LiTaO.sub.3 at room temperature, namely, voltage before the occurrence of voltage breakage.
With regard to the injection charge for the above-mentioned domain inversion, since the charge during spontaneous polarization on the surface of LiTaO.sub.3 substrate is generally electrically neutralized with positive ion or electron, in the case of domain inversion by the application of electric field, the total amount of injected charge doubles during spontaneous polarization, upon injection of positive charge from the upper electrode, as in the case of domain inversion by electron beam irradiation, due to the neutralization of the surface charge and generation of electric field by domain inversion.
In the embodiment shown in FIG. 13, the injected charge measured was 27.6 .mu.C which is almost the same as 28.0 .mu.C by calculation. The injected charge corresponds to the area of the pattern of the patterned electrode. Therefore, it can be used as a parameter of domain control.
[Generation of second harmonic by quasi-phase matching]
In the generation of a second harmonic by a LiTaO.sub.3 crystal, the relationship between the wavelength of the fundamental wave when QPM order is first order (m=1) and second order (m=2), and the period of domain inversion as calculated by the formula (2) is expressed by the solid line in FIG. 15.
The evaluation test of LiTaO.sub.3 which underwent periodic domain inversion by the application of direct voltage by the above-mentioned patterned electrode was run by input-processing the output of the second harmonic by a computer, while continuously sweeping the oscillation wavelength of Ti:Al.sub.2 O.sub.3 (titanium sapphire) laser.
The relationship between the generation intensity of second harmonic at different domain periods T, namely, 7.5 .mu.m, 7.8 .mu.m and 8.1 .mu.m and the wavelength .lambda..sub.F of the fundamental wave at the .circleincircle. wherein order m=2 in FIG. 15, is shown in FIG. 16.
The double-dotted line in FIG. 15 represents the value at wavelength 1064 nm of Nd:YAG (neodymium.yttrium.aluminum.garnet) laser widely used as a solid-state laser, which indicates quasi-phase matching at a domain period of 7.8 .mu.m.
In addition, the width of the synchronization spectrum of fundamental wave at the generation intensity of second harmonic relative to each domain period T, namely, half-value breadth, was ca. 0.81 nm and almost the same for the three curves in FIG. 16.
Since the theoretical value of this width is 0.74 nm, the periodic domain inversion parts are considered to have been almost uniformly prepared, though with standard error within the range of experimental manufacture error. In addition, the experiment on the .circleincircle. point wherein m=1 in FIG. 15 was for the confirmation by the output of optical parametric oscillation. In this case again, the experimental results match well with the calculation results.
Since the light wave is subject to diffraction during transmission, it is essential for a the most efficient generation of second harmonic to collect light wave of the wavelength corresponding to the length of beam path in an optical device, namely, the length of the device. Under the conditions wherein conforcal length of the gauss beam and the above-mentioned device length were synchronized, the conversion efficiency .eta..sub.b is calculated from the following formula. ##EQU3##
wherein P.sub.SH is output of second harmonic, P.sub.F is input of fundamental wave, L is device length mentioned above, c is light speed, .mu..sub.0 is permeability of vacuum, .epsilon..sub.0 is permittivity of vacuum, .omega..sub.F is angular frequency of fundamental wave and d.sub.eff is effective second order nonlinear optical coefficient.
The reason for using the second order nonlinear optical coefficient here is that the nonlinear optical coefficient includes all nonlinear optical coefficients, such as second order, third order, fourth order and so on, but the generation of second harmonic by quasi-phase matching requires the use of only second order nonlinear optical coefficient.
In QPM wherein m=2, P.sub.F was 32 mW, L was 4 mm and P.sub.SH was 1.9 .mu.W.
From these results, it is known from formula (3) that the experimental value of .eta..sub.b was 0.46%/W cm. Since the duty ratio .xi. of the domain inversion structure prepared was ca. 0.63 by measurement, .eta..sub.b was 0.48%/W cm, similarly from formula (3). This means that the experimental value and the theoretical value are almost the same. However, by setting the duty ratio .xi. to an optimal value of 0.5, the value of normalized conversion efficiency .eta..sub.b can be increased by about 20%.
On the other hand, for efficient optical parametric oscillation utilizing the above-mentioned QPM, the distance between the reflecting mirrors of the oscillator, which are separately set at the both ends of an optical crystal, is changed to achieve harmonization with the excitation wave input as an oscillation source.
Further, a method using Q switching may be employed to obtain the oscillation output by such laser as pulsed output having a greater peak. The structure of such Q switching may be one wherein a saturatable absorption cell formed separately from optical crystal is placed on or off the oscillation path, or one wherein ultrasound output to be applied to an ultrasound switch formed separately from an optical crystal is changed, which are disclosed in Reference 16 and others.
According to the above-mentioned prior art techniques, almost all parts in the structures used to obtain output light by harmonic based on QPM or by frequency conversion, or optical parametric oscillation based on QPM, have individual structures. In these structures, a fine oscillation adjustment operation to achieve oscillation by changing the distance between the reflecting mirrors of the oscillator, fine adjustment operation to align optical axis with the direction of the optical axis of the lens and Q switch, and the like are necessary.
Therefore, an optical device comprising a single element constituting these parts, which permits electronic adjustment operation, will be extremely convenient for users. It remains to be solved, however, how to constitute such optical device.


A transmission control method improves shift feel during kickdown shifts. The release clutch is fully released at the initiation of the kickdown shift. The release clutch is then reapplied when the volume of the release clutch reaches a threshold capacity. The volume of the release clutch is slowly ramped down, thereby increasing turbine speed. When the turbine speed reaches a threshold, the apply clutch is actuated. The apply clutch is actuated by controlling the volume of the apply clutch according to a target volume.

Due to relatively high instances of system inertia and delay in automotive transmissions, feedback control of various components in automotive transmissions is not appropriate for certain transient elements. Control of transmission turbine speed during a kickdown shift is one example of a transient condition in automotive transmissions. During a kickdown shift, such as a drop from 4th gear to 3rd gear, or from 3rd gear to 2nd gear, the speed of the turbine must increase to correspond to a targeted gear ratio. Additionally, the acceleration of the turbine must be controlled to correspond to a targeted acceleration according to current vehicle acceleration. In such transient cases, feedforward control can be used to anticipate system changes. For example, mixed feedforward and feedback control can be used for a smooth kickdown shift without causing significant "feel" issues for the driver, thereby improving overall shift quality. Shift quality has been shown to be an important factor for driver satisfaction.
Automotive transmissions may use accumulators to absorb apply pressure fluid during certain shift operations. The presence of the accumulator reduces sensitivity of torque variations in torque phase during shifts. However, accumulators cause the pressure response to be slower and more difficult to predict since the solenoid current directly controls the flow rate and indirectly controls the pressure. With reference to FIG. 1, a typical accumulator 10 includes one or more springs 12 and a piston 14. Fluid fills the accumulator 10 and compresses the spring 12. The volume of the accumulator 10 varies over the usable range of the spring 12, and is indicative of the volume of a particular shift element in the transmission. The volume of the shift element is a further indicator of the capacity of the shift element, which may be used for control purposes. Target volume kickdown logic determines a target volume for the shift element, and subsequently calculates a change in shift element volume required for proper control. Control based on target volume can be used to calculate changes in element capacity or volume that are required to achieve target acceleration. As a result, excessive runaway or harshness during shifting is prevented.
Target volume control can be determined according to desired volume change due to turbine inertia force and/or desired volume change due to engine inertia force. Conventionally, empirical methods are used to determine target volume control. For example, change in volume can be calculated according to relationships between turbine inertia force, engine inertia force, accumulator pressure, and/or release element clutch pressure. However, such empirical methods are not particularly accurate in practice because turbine acceleration and engine acceleration each belong to independent dynamic systems. Therefore, the release element clutch cannot directly control engine acceleration. When the release element clutch is used to control turbine acceleration, turbine torque from the engine must be assumed as a fixed input through the torque converter and is a function of slip speed between the engine and the turbine.
If only the engine dynamic system is considered, the engine resistance torque, or turbine torque, can be changed to control engine acceleration if the throttle opening is fixed. However, turbine torque, or engine resistance torque, that is required to control the engine acceleration into a desired acceleration is different from the fixed turbine torque when turbine acceleration is controlled into a desired value. The control may be overcompensated because the torque required to change the engine acceleration is much larger than the turbine torque received from the engine. Therefore, it is desirable to provide optimized control during a kickdown shift to further improve shift quality. A continuous variable and speed-based desired acceleration method to provide consistent and accurate transmission control based in part on accumulator pressure is proposed.

Model based kickdown shift method for clutch to clutch shift transmissions with accumulators


Prior power generation systems generated output voltages having relatively large, undesirable overvoltage transients due sudden load reduction. In order to overcome this disadvantage, a power generation system for generating a DC bus voltage on a DC bus is provided with a switch coupled across the DC bus to suppress overvoltage transients. The power generation system includes a synchronous generator that generates AC power and a rectifier that rectifies the AC power to produce DC power and supply the DC power to the DC bus. A voltage regulator controls magnitude of the DC bus voltage by varying the amount of current provided to a field winding associated with the synchronous generator. A switch is coupled across the DC bus and is repeatedly switched when the DC bus voltage reaches a predetermined magnitude. When the switch is in operation, the voltage regulator controls the DC bus voltage based upon an emulated voltage generated by a voltage emulator.

Power generation systems, such as those used in aircraft, are conventionally used to generate electrical power from the aircraft engines to provide both DC and AC electrical power for numerous components of the aircraft such as lights, controls, cockpit instruments, etc. via a DC link and an AC link, respectively.
During operation of the aircraft, the electrical power supplied by the power system may exhibit overvoltage transients if the load is suddenly removed. These overvoltage transients may occur in the DC power supplied on the DC link and/or in the AC power supplied on the AC link. These overvoltage transients are undesirable, and may cause damage to the aircraft components connected to the respective DC or AC link.
Various attempts have been made to reduce or eliminate the harmful effects of such overvoltage transients. For example, U.S. Pat. No. 4,225,911 to Carlson discloses an electrical power system for an aircraft having means for reducing overvoltage transients in the AC power generated by the system. The Carlson system operates by sensing the magnitude of the current generated by the system in each of the three AC power lines, and then altering the magnitude of a feedback control signal based thereon to control the magnitude of the AC power generated.
U.S. Pat. No. 4,439,722 to Budnik discloses a stabilization circuit for use with a power supply to maintain a steady DC output voltage during power line transients, rapid load changes, or no-load conditions. The Budnik stabilization circuit is responsive to the output voltage of the power supply and selectively connects a load across the output terminals of the power supply. Although it may act to suppress overvoltage transients in the DC power provided, the Budnik circuit provides only relatively short term control of the output voltage.

Power generation system with transient suppressor


A system for evacuating a reactor chamber includes a main evacuation line connected at one end thereof to the reactor chamber and at another end thereof to a means for creating a partial vacuum. A valve in the main evacuation line divides the line into a chamber side and a vacuum side. A second line is connected at one end to the vacuum side of the main evacuation line and at another end to a fluid supply source. As the valve in the main evacuation line is opened, fluid is supplied through the second line to the main evacuation line to prevent rapid, turbulence-inducing pressure drops in the reactor chamber.

1. Field of the Invention
The present invention generally relates to systems for manufacturing semiconductor integrated circuits and, more particularly, to pumping systems for evacuating reactor chambers that are used in the manufacture of semiconductor integrated circuits.
2. State of the Art
In the manufacture of semiconductor integrated circuits, it is typical to employ chambers from which air has been evacuated. During the evacuation of such reactor chambers, significant turbulent effects can be caused. When the reactor chamber is used in the manufacture of semiconductor integrated circuits, turbulence is highly undesirable. Specifically, during the manufacture of semiconductor integrated circuits, silicon wafers are generally introduced into a reactor chamber at atmospheric pressure and the reactor chamber is then degassed and the wafers are then treated with one or more reagents introduced into the reactor chamber which are used to modify the wafer.
In practice, turbulence can result in defects in the semiconductor integrated circuits. Specifically, particulate matter may collect within a reactor chamber by, for example, adhering to the walls of the reactor. Then, when turbulence is created within the reactor chamber, usually at the entrance to the evacuation line, particulate matter is caused to dislodge from the walls and can contaminate the wafers that are being processed. The wafer contamination can cause the semiconductor integrated circuits to be defective.
Workers in the art of fabricating semiconductor integrated circuits have attempted to control the turbulence that occurs in the reactor chamber as large volumes of fluid (e.g., air) in the reactor chamber are suddenly removed through the evacuation line. For instance, turbulence in evacuation chambers has been reduced by placing a valve in the evacuation line between the reactor chamber and a means for creating a partial vacuum includes a pump and a blower. The opening of the valve, shown in FIG. 1, is regulated such that, as evacuation begins, the valve is only slightly opened and flow is minimal. As the pressure drop across the valve decreases, the valve is slowly opened further, thus preventing large, turbulence-inducing flow rates. Also, a series of valves can be mounted in the evacuation line such that each set of two valves provides, in effect, a separate chamber. When it is desired to evacuate a reactor chamber, the opening of each valve can be set to produce a series of gradual pressure drops. However, in the case of the reactor chamber for semiconductor integrated circuits, the reactor chamber is typically at atmospheric pressure and a pump and blower causes a pressure drop to approximately 10 millitorrs. It has proven to be very difficult to control fluid flow in relatively large diameter evacuation lines, and these techniques for reducing turbulence during evacuation have produced largely unsatisfactory results. Turbulent effects have proven to be particularly in evidence when flow from the reactor chamber to the evacuation line is first being established.
In view of the shortcomings in prior art systems for controlling fluid flow in large diameter evacuation lines, workers in the art have attempted to reduce turbulence during evacuation of reactor chambers by connecting a second, smaller diameter line with a controllable valve between the reactor chamber and the portion of the main evacuation line near the means for creating a partial vacuum. Such solutions have, however, been found to be wanting in precision. Again, the large pressure drop that must occur between the opening to the slow pump line in the reactor chamber and the end of the slow pump line has been found to almost inevitably cause some turbulent effects in the reactor chamber. Further, it has been found that contaminants collect in the slow pump line itself and add to the contamination of the reactor chamber.

Pumping system for evacuating reactor chambers


A method of making a semiconductor chip package by attaching a chip to a dielectric layer; placing the dielectric layer and chip into a mold; disposing a thixotropic composition that has bee sheared to reduced its viscosity into the mold and curing the thixotropic composition after the chip and dielectric layer have been removed from the mold.. A method of making a semiconductor chip package without using a mold by disposing a sheared thixotropic composition between a semiconductor chip and a dielectric layer and then curing the thixotropic composition to form a cured encapsulant.. A method of making a semiconductor chip package without using a mold during the curing step and without the need to use a thixotropic composition by placing a semiconductor chip attached to a dielectric layer into a mold and disposing a liquid composition between the chip and the dielectric layer, forming a cured skin on the liquid composition, removing the work-piece from the mold and then completely the cure of the liquid composition.

1. Field of the Invention
The present invention relates to art of microelectronic packaging and more specifically to methods of encapsulating a semiconductor chip package using a pseudoplastic encapsulant having thixotropic properties.
2. Description of the Related Art
In the construction of semiconductor chip package assemblies, it has been found desirable to interpose an encapsulant between and/or around elements of the semiconductor package. An encapsulant may be used in an effort to reduce and/or redistribute the strain and stress on the connections between the semiconductor chip and the supporting circuitized substrate during operation of the chip. An encapsulant may also serve to seal the elements against corrosion, as well as to insure intimate contact between the encapsulant, the semiconductor chip and the other elements of the chip package.
Semiconductor chip packages are often encapsulated using liquid compositions that cure to form encapsulants. Such compositions frequently cure upon exposure to elevated temperatures. In order to encapsulate a semiconductor package, the liquid composition is dispensed or injected into the package. Often, a mold or fixture is placed around the package prior to dispensing the liquid composition. The mold is then placed in oven to cure the liquid composition. Once the composition is cured, the mold is removed from the oven and the package is removed from the mold. It would be desirable to remove the semiconductor chip package from the mold before curing the composition because the cure time of the composition is extended when the package is encased in the mold.
Methods of using curable liquid compositions to encapsulate semiconductor chip packages are described in, for example, commonly assigned U.S. Pat. No. 5,659,652; U.S. Pat. No. 5,766,987; U.S. patent application Ser. No. 09/067,698 filed Apr. 28, 1998; U.S. patent application Ser. No. 08/610,610, filed Mar. 7, 1997; and U.S. Pat. No. 5,776,796, the disclosures of which are incorporated herein by reference. In certain embodiments of such patents and applications, a microelectronic assembly having a semiconductor chip and a flexible, sheet-like dielectric element is disclosed. Contacts on the chip are electrically interconnected to terminals on the dielectric element. The assembly may also include a compliant layer such as an elastomer or gel disposed between the dielectric sheet and the chip to provide mechanical decoupling of the sheet and terminals from the chip. As disclosed in the aforementioned patents and patent applications, such compliant layers can be made by providing a porous layer, such as a plurality of compliant pads, between the chip and the dielectric sheet, electrically connecting the terminals to contacts on the chip and then encapsulating the resulting assembly with a curable liquid composition so that the composition penetrates into the porous layer and also covers the connections at the contacts on the chip. Upon curing, the composition forms a compliant encapsulant which becomes part of the compliant layer. In making assemblies of this nature, it is desirable to ensure that the encapsulant completely fills the porous layer, to provide a substantially void-free compliant layer in the final assembly.
Several useful methods of applying and curing the encapsulant in microelectronic assemblies have been proposed in commonly assigned, copending United States patents applications and patents. For example, as set forth in the aforementioned U.S. Pat. No. 5,766,987 patent, coverlays may be applied over the top and bottom surfaces of the assembly. Typically, several assemblies are provided in a side by side arrangement so the same top coverlay lies on the top surfaces of several assemblies. The coverlay and assembly are held in a fixture. After the space between the coverlays is brought to sub-atmospheric pressure, the fixture is tilted and the liquid encapsulant is poured into the space between the cover layers. The encapsulant is then cured while the components remain in place in the fixture.
As described in U.S. Pat. No. 5,659,952, the disclosure of which is incorporated herein by reference, and the aforementioned U.S. Pat. No. 5,776,796, the encapsulant may be applied using a nozzle or a syringe around the periphery of each subassembly. For example, as shown in the '796 patent, a plurality of assemblies can be made using a single, unitary dielectric sheet element which incorporates the dielectric sheets of several subassemblies. The chips may be attached to the dielectric sheet and electrically connected to the terminals of the dielectric sheet. At this point, a needle connected to an encapsulant dispenser is used to trace a pattern around the peripheries of the individual chips, so that the encapsulant flows into the space between each chip and the dielectric layer. A coverlay may be used to close the bond windows in the dielectric sheet during this process. Also, during this process, the dielectric sheet typically is held in a frame. In a further variant of this process, described in U.S. patent application Ser. No. 08/975,590 filed on Nov. 20, 1997, the disclosure of which is also incorporated by reference herein, the frame and dielectric sheet are placed in a vacuum chamber, and the encapsulant dispensing operation is conducted inside the chamber, while the assembly is under vacuum. When the vacuum is released, and the chamber is brought to atmospheric or superatmospheric pressure, the pressure forces the encapsulant into the porous layer between the chip and the dielectric sheet. Further, as described in U.S. patent application Ser. No. 09/012,590, filed Jan. 23, 1998, the disclosure of which is also incorporated by reference herein, it is convenient to use a frame to hold the dielectric sheet during the assembly procedures. The frame allows for mechanical handling of the dielectric sheet without direct contact with the portions of the sheet which will be incorporated into the final assembly. For example, the compliant pads used to form the porous layer may be applied to the dielectric sheet while the dielectric sheet is mounted on the frame and the chips may be mechanically attached to the pads and electrically connected to the terminals also while the dielectric sheet is mounted on the frame.
Other methods of encapsulating an assembly are disclosed in the aforementioned application Ser. No. 09/067,698. In certain embodiments of such application, for example, the encapsulating method includes the steps of providing a plurality of assemblies within an opening in a frame and providing top and bottom sealing layers which are sealingly connected to the frame and which extend across the opening of the frame. The top and bottom sealing layers together with the frame define an enclosed space encompassing the assemblies. The frame, sealing layers and assemblies are engaged in a fixture as, for example, by clamping the frame and sealing layers between top and bottom elements of the fixture. While the frame is engaged in the fixture a liquid encapsulant is injected into the enclosed space, between the sealing layers and around the assemblies. The encapsulant is then cured. After curing, the assemblies may be further processed before singulation or may be removed from the frame and severed from one another. While the above described inventions offer important advantages, still other improvements are desirable.

Methods of encapsulating a semiconductor chip using a settable encapsulant


A hollow wall having a plurality of spaced, vertical studs, wallboards affixed to both sides of the plurality of studs, and septum panels disposed within the hollow of the wall, held firmly in place by small pieces of board, with one such piece of board on each side of the septum panels, at each side edge, extending through an opening in a stud.

Hollow walls with 1/2 inch gypsum wallboard on each face have been made more fire-retardant or more sound-proof by the inclusion within the hollow space between adjacent studs of an additional piece of gypsum wallboard, referred to as a septum panel. This additional piece of wallboard or septum panel was not affixed to anything, but, instead, simply lay slightly diagonally against one of the wallboards forming one of the wall faces.
Determination of the fire-retardant characteristics of a wall involves a fire test in which the wall is subjected, first, to the heat of a fire against one face of the wall, in special fire testing furnaces. Almost immediately after being removed from this furnace the heated face of the wall is subjected to a hose stream test in which a stream of water, under considerable pressure, is maintained, impinging on the heated face. In testing a hollow wall with a loosely disposed septum panel inside, it was noted that the loosely disposed septum panel was moving back and forth as the hose stream was moved first crosswise over various parts of the wall, then vertically over various parts of the wall, then crosswise, etc. It was further noted that this movement of the septum panel was contributing to the tendency of the wall to fail the hose stream test, by causing some part of the wall to open up and permit water to pass through the wall and project out from the remote side.


A 6T static random access memory cell, array, and memory thereof are provided, in which the memory cell includes a first inverter, a second inverter, a first access transistor, and a second access transistor. The first inverter and second inverter respectively include a first pull-up transistor, a first pull-down transistor, a second pull-up transistor and a second pull-down transistor. The first pull-down and pull-up transistors each have a drain terminal mutually coupled to form a first node. The second pull-down and pull-up transistors each have a drain terminal mutually coupled to form a second node. The first and second access transistors each have a gate terminal respectively coupled to a first word line and a second word line. When the first word line provides on signals to turn on the first access transistor, the second low voltage supply provides a first differential voltage simultaneously.

1. Field of the Invention
The instant disclosure relates to a static random access memory cell; in particular, to a 6T static random access memory cell, array, and memory thereof.
2. Description of Related Art
In order to reduce the required power consumption, minimizing the size of the integrated circuit memory devices in semiconductors is still the direction to strive for. Memory devices in semiconductors include static random access memory (SRAM) and dynamic random access memory (DRAM). DRAM memory cell only has one transistor and a capacitor, which provides high integrability. However, since DRAM required continuous replacements, high power consumption and slow speed makes DRAM a memory choice limited to mostly computer memories. On the other hand, SRAM cell has bistability, which means with the appropriate power, SRAM can continuously maintain the original state. SRAM can operate in high speed under low power consumption such that computers mostly use a lot of cache SRAM. Other applications include embedded memory, and network device memory.
Conventional structures of common SRAM cells include six transistors (6T) having 6 MOS transistors. Please refer to FIG. 1 as a circuit diagram of a conventional 6T static random access memory cell. The conventional 6T static random access memory cell 1 includes a first inverter 11, a second inverter 12, a first access transistor M5, and a second access transistor M6. The first inverter 11 includes a first pull-up transistor M1 and a first pull-down transistor M3, whereas the second inverter 12 includes a second pull-up transistor M2 and a second pull-down transistor M4. The first pull-up transistor M1 has a source terminal and the second pull-up transistor M2 has a source terminal cooperatively couple to a voltage supply VDD. The first pull-down transistor M3 has a source terminal and the second pull-down transistor M4 has a source terminal cooperatively couple to a low voltage supply VSS. The first pull-down transistor M3 has a drain terminal and the first pull-up transistor M1 has a drain terminal cooperatively couple to form a first node Q. The second pull-down transistor M4 has a drain terminal and the second pull-up transistor M2 has a drain terminal cooperatively couple to form a second node QB.
The first access transistor M5 has a gate terminal coupled to a word line WL, a source terminal coupled to the first node Q, and a drain terminal coupled to a first bit line BL. The second access transistor M6 has a gate terminal coupled to the word line WL, a source terminal coupled to the second node QB, and a drain terminal coupled to a second bit line BLB.
Please refer to FIGS. 1 and 2. FIG. 2 is a signal diagram of the conventional 6T static random access memory cell while data are being written thereon. Conventional 6T static random access memory cell 1 must fix the first bit line BL and the second bit line BLB to a group of fixed voltage when data are being written, such that data stored in the first node Q and the second node QB are forced to flip.
Please refer to FIGS. 1 and 3. FIG. 3 is a signal diagram of the conventional 6T static random access memory cell while data are being read therefrom. Conventional 6T static random access memory cell 1 must pull the electric potential of word line WL to "1" (refer to T3˜T4 interval as shown in FIG. 3) when data being read, which is different from writing, the electric potential of the first bit line BL must pull up and equal to the second bit line BLB before the electric potential of the word line WL pulls up to "1", the first bit line BL and the second bit line BLB must have equal electric potentials such as "1" as shown in FIG. 3. When the first bit line BL is equal to the second bit line BLB and floating, the word line WL then provides on signals. The conventional 6T static random access memory cell uses the storage values of the first node Q and the second node QB and, via the first access transistor M5 and the second access transistor M6, and generates charge sharing and voltage division respectively with the first bit line BL and the second bit line BLB, such that difference in electric potential is induced between the first bit line BL and the second bit line BLB. As shown in FIG. 3, electric potential signal of the first bit line BL is affected, thus voltage is reduced. Successively, external signal amplifier (not shown in figures) amplifies differences in signals and read out voltage value as "0" or "1".
However, when the conventional 6T static random access memory cell 1 is reading data, the first node Q and the second node QB are prone to mutually interfere which prevent the stored values from smoothly flipping. As shown in FIG. 2, it is impossible to flip the voltage values of the first and second node Q, QB such that writing fails during time intervals T1 and T2. Moreover, as shown in FIG. 3, when the conventional 6T static random access memory cell 1 is reading, the voltage values of the first and second node Q, QB will mutually interfere in time intervals T3 and T4 due to voltage division. In turn, unexpected flipping of originally stored data might occur when data is being read, thus providing erroneous data. As a result, there is still much room for improvement in SRAM design.
To address the above issues, the inventor strives via associated experience and research to present the instant disclosure, which can effectively improve the limitation described above.

6T static random access memory cell, array and memory thereof


A switching power supply circuit includes a switching element connected to a primary winding wire of a transformer in series, capacitors connected to secondary winding wires of the transformer via diodes, and an IC for power supply control that controls ON/OFF operation of the switching element on the basis of a charged voltage of the capacitors. Commanded voltages are charged in the capacitors after electric power is supplied to a main power supply, and further, after the elapse of a delay time set in advance, a control circuit, which controls the entire apparatus, controls a main circuit and a peripheral apparatus circuit to start operations.

In general, various electronic apparatuses such as home electronics, industrial apparatuses, and vehicle-mounted apparatuses are configured by a plurality of circuits. For example, a power conversion apparatus represented by an inverter apparatus that variably controls the speed of a motor is configured by a main circuit including a power module that supplies alternating-current power to the motor, a peripheral apparatus circuit that drives a cooling fan to cool the heated power module and operates apparatuses not directly related to control and operation of the motor, a control circuit that is mounted with an arithmetic processing device such as a microcomputer, a CPU, an ASIC, or an FPGA and transmits a motor driving signal to the main circuit, which drives the motor, and controls the overall control of the power conversion apparatus such as the operation of the peripheral apparatus circuit, a power supply circuit that supplies electric power serving as a power source for these circuits, and the like.
In general, as the power supply circuit, a switching power supply circuit with high conversion efficiency is used. In the case of the power conversion apparatus explained above, to eliminate the influence of noise transmitted from a main power supply serving as the power source for the power supply circuit or for a reason such as electric shock prevention, a switching power supply circuit including an insulated transformer is used.
The switching power supply circuit is configured by components such as a switching element, an insulated transformer including a primary winding wire and one or a plurality of secondary winding wires, a main power supply being connected to the primary winding wire via the switching element, a diode connected to the secondary winding wire(s) of the insulated transformer, a capacitor connected to the secondary winding wire(s) of the insulated transformer via the diode, and an IC for control power supply control that controls ON/OFF of the switching element. The IC for power supply control controls ON/OFF of the switching element on the basis of a voltage value of the capacitor. Basically, the switching power supply circuit controls a flow of electric power according to this ON/OFF operation.
When the insulated transformer includes one secondary winding wire, the IC for power supply control performs the control of ON/OFF of the switching element on the basis of the voltage value of the capacitor connected to the secondary winding wire via the diode. On the other hand, when the insulted transformer includes a plurality of secondary winding wires, in general, the IC for power supply control performs the ON/OFF control of the switching element on the basis of the voltage value of the capacitor connected to a certain one secondary winding wire via the diode.
In general, the IC for power supply control has a function of performing the ON/OFF control of the switching element on the basis of the voltage of the capacitor connected to the secondary winding wire(s) via the diode and a function of monitoring an electric current flowing to the primary winding wire and the switching element and, when an excessively large electric current flows, performing overcurrent protection for forcibly turning off the switching element.
The switching power supply circuit has a state in which, when a power supply is turned on, there is no voltage of the capacitor connected to the secondary winding wire(s) of the insulated transformer via the diode (hereinafter referred to as "start time or during start") and a state in which electric power generated by the secondary winding wire(s) of the insulated transformer is stably supplied and the voltage of the capacitor reaches a desired voltage set in advance (hereinafter referred to as "commanded voltage") (hereinafter referred to as "steady time or steady state").
At the start time, because power energy accumulated in the primary winding wire of the insulated transformer increases, an excessively large electric current flows to the primary winding wire and the switching element. Therefore, the overcurrent protection operation of the IC for power supply control works and the switching element is forcibly turned off. Thereafter, the overcurrent protection operation is released and the switching element is turned on again. However, the switching element is turned off by the overcurrent protection operation performed again. This operation is repeated, a voltage is charged in the capacitor connected to the secondary winding wire(s) via the diode, and the switching power supply circuit changes to the steady state.
On the other hand, in the steady state, the voltage of the capacitor connected to the secondary winding wire(s) via the diode is charged to the commanded voltage, an excessively large electric current does not flow to the primary winding wire and the switching element. However, when there is some abnormality in the switching power supply circuit, the circuit connected to the secondary winding wire(s), or the like and an excessively large electric current flows to the primary winding wire and the switching element, the overcurrent protection operation of the IC for power supply control works.
The overcurrent protection operation of the IC for power supply control is for preventing thermal destruction of the switching element and the diode, which are the components of the switching power supply circuit, magnetic saturation of the insulated transformer, and the like. If a current value for operating the overcurrent protection (hereinafter referred to as "overcurrent protection level current value IDOC") can be reduced, when some abnormality occurs in the switching power supply circuit, the circuit connected to the secondary winding wire(s), or the like and an excessively large electric current flows to the primary winding wire or the switching element, the operation of the switching element can be quickly interrupted. Therefore, as the switching element and the diode having small heat capacities can be adopted, and the magnetic saturation of the insulated transformer can be prevented, a reduction in the size of the insulated transformer can also be attained.
For example, when a load of the circuit connected to the secondary winding wire(s) via the diode increases because of some abnormality, an excessively large electric current flows to the secondary winding wire(s) and the diode and, and at the same time, an electric current flowing to the primary winding wire and the switching element also increases. If the electric current flowing to the primary winding wire and the switching element reaches the overcurrent protection level current value IDOC, the switching element is forcibly turned off and the power supply to the secondary winding wire(s) is stopped.
However, when the overcurrent protection level current value IDOC is reduced, at the start time of the switching power supply circuit, sufficient power energy cannot be accumulated in the primary winding wire and a desired voltage cannot be charged in the capacitor connected to the secondary winding wire(s) via the diode. Therefore, it is necessary to set the overcurrent protection level current value IDOC with which the commanded voltage can be charged in the capacitor.
Because of the reasons explained above, to set the overcurrent protection level current value IDOC necessary at the start time, the switching element and the diode having large heat capacities unnecessary at the steady time are made necessary. At the same time, there is also a problem in that the insulated transformer is also increased in size for magnetic saturation prevention of the insulated transformer, the switching power supply circuit is increased in size, and costs increase.
As measures against the problems, Patent Literature 1 described below discloses a technology for changing the overcurrent protection level current value IDOC of the IC for power supply control, that is, a technology for monitoring, with the IC for power supply control, a voltage value of the capacitor serving as a power source of the IC for power supply control and connected to an auxiliary winding wire by the diode and changing an overcurrent protection level current for an electric current flowing to the primary winding wire and the switching element. For example, when the voltage value of the capacitor is low, it is determined that the switching power supply circuit is at the start time or an overload, a short circuit, or the like of the circuit connected to the secondary winding wire(s) has occurred, and the IC for power supply control operates to set a small overcurrent protection level current value IDOC (hereinafter referred to as "overload time overcurrent protection level current value IDOC"). When the voltage value of the capacitor reaches the commanded voltage, it is determined that the switching power supply circuit is in the steady state. The IC for power supply control operates to set the conventional overcurrent protection level current value IDOC (hereinafter referred to as "conventional overcurrent protection level power supply value IDOC"; and is set to a value larger than the overload time overcurrent protection level current value IDOC). Only at the start time, a change of the overcurrent protection level current value IDOC is prohibited to quickly perform the start of the switching power supply circuit. According to the operation explained above, the heat capacities of the diode and the switching element can be reduced. Therefore, it is possible to reduce the size of the components of the switching power supply circuit.

Switching power supply circuit and control method therefor


A display device comprises a display unit and a display supporting unit. The display supporting unit includes a base including a body and at least three stands. The bottom of the body includes a center hole. The stands are connected to the body. A support arm, an end of the support arm is sleeved on the base. A light emitting unit is disposed at the support arm adjacent to the base. A light cover is disposed at the support arm between the light emitting unit and the center hole of the body.

Field of the Invention
The disclosure relates to a display device.
Description of the Related Art
Display is an important electronic device in people's daily life and work. People might use several displays simultaneously to display different information.
The display usually needs to be adjusted its angles relative to a user and a tabletop according to the position or use status. For example, when multiple displays are used simultaneously, the displays are arranged around a user. However, displays on the market usually match fixing bases. To move or rotate the display relative to the tabletop, the display should rotate along with the fixing base, or an additional rotatable support arm is assembled for the movement or rotation.


An automotive building machine comprising a material bunker for accommodating therein pavement material to be laid is provided, the building machine being a road finisher or a charger. The material bunker comprises at least one lifting device, which is adapted to enter into releasable engagement with a movable tailgate of a truck supplying the material bunker with the pavement material and which is configured for displacing the movable tailgate of the truck between a first position and a second position. A method used for this purpose is also provided.

It is known that, during a charging process, a material supply vehicle, e.g., a truck, backs up to a material bunker of a road finisher or a charger and, if necessary, docks onto a docking device of the road finisher or of the charger, at least temporarily, during the charging process. A docking device provided for this purpose is furnished e.g., by the applicant's PaveDock system, which is described especially within the framework of European patent application No. 14164376.7, whose disclosure is herewith incorporated by reference.
For filling the material bunker of the road finisher or of the charger, the material supply vehicle, e.g., the truck, backs up to the material bunker such that the rear part of the load platform of the material supply vehicle projects, at least partially, into a charging area of the material bunker, so that, when the load platform is tilted, the pavement material will slide from the load platform into the material bunker.
Traditionally, the load platform of the material supply vehicle comprises a tailgate, which is opened during the material transfer process to the material bunker, when the material supply vehicle tilts the load platform. When the load platform of the material supply vehicle is being lifted, the tailgate is maintained at a position enforced by gravity substantially perpendicular to the ground, and it may additionally be forced open backwards by the pavement material sliding down the load platform.
A circumstance causing problems is that, when the material is being transferred, the tailgate of the truck projects far into a charging area of the material bunker of the road finisher or of the charger and may perhaps collide with material bunker walls or with components, such as augers, installed in the material bunker.
In addition, the hanging-down tailgate may prevent a uniform distribution of material during material transfer to the material bunker of the road finisher or of the charger, since the pavement material sliding down the load platform strikes against the tailgate and is then guided predominantly into a front area of the material bunker. This results in non-uniform filling of the material bunker, whereby additional efforts may be required or the laying process may even be interrupted.

Building machine with lifting device for a charging process


A sound responsive color organ includes a transducer to convert sound to electricity, an amplifier to increase the level of electricity, and an automatic gain control that operates under the influence of a time dependent circuit to control the output level of the amplifier. The time dependent circuit operates at one rate when increasing the amplifier gain and at a second rate when decreasing the amplifier gain. A network is included to adjust the frequency response of the amplifier to predetermined limits. The amplifier output is used to control switching devices that turn on and/or off lights in a display located behind color masks. Located in front of the color masks is a lenticular surface which further affects the light sources to yield geometric patterns comprising the effect of the masks and the lens types.

1. Field of the Invention
The present invention relates to audio responsive devices, and more particularly to audio responsive color generators sometimes referred to as color organs.
2. Description of the Prior Art
Color generators or organs have been frequently used in the past either to provide entertainment or to serve as an advertising medium. In recent past the use of audio coupling has become quite prevalent and color organs coupled to sound are now easily found in the market place. Most frequently an audio transducer is used to provide the coupling, the organ including amplitude and frequency selection features which, by adjustment, are set to respond to the audio signal and to turn on lights. Typically devices of this kind operate on a threshold principle; the loudness of the received audio signal determining the setting of the light. The difficulty however, arises in the variations in loudness with each performance or song where in one instance the levels are constantly above the threshold, or alternatively, the threshold is never reached.
To overcome this problem variable gain controls have been utilized in the recent past which, according to the average signal, effectively vary the threshold. Gain control of this kind, however, also has some undesired features since it takes the same time constant to increase the gain as it takes for a decrease. Accordingly, as loudness changes within a song or performance, the response rate also changes.


For use in rear turbine stabilized helicopters, a air foil blade comprising an integrally formed and readily replicated spar and blade in which the blade is created from compounded plastic having cellular structure and adherent to the spar. The air foil blade is produced by a unique adaptation of an injection molding process using a foamed polypropylene thermoplastic material.

Rear turbine stabilized helicopter, the so-called "Notartype", are a new generation of helicopters which are characterized by the use of an internal turbine-like mechanism in the tail section of the craft to steer and stabilize the craft. The turbine replaces the traditional rear external blade (so-called "tail rotor") which heretofore has caused numerous spin-outs and fatal crashes.
The rear turbine comprises a housing having a plurality of air foil blade assemblies arranged therein to form a turbine or fan-like device in the tail section of the air craft. In theory, the placement of a blade turbine in the tail assembly and the venting of the combustion gases from the prime motor through that turbine to counteract the torque of the main rotor proved sound. In practice, however, it was not reliable because the air foil blades had to be hand made and were constructed of a hand laminated fiberglass covering which was disposed upon a rubber core. This construction disintegrated on use and caused the pilot to lose the degree of aircraft control needed for safe flight. In addition, the discrepancies between hand crafted blades created an extraordinary high percentage of rejects.
As indicated above, the prior art air foil blades were produced by telescopically disposing a blade in the end of a metal spar and thereafter covering the assemblage by a hand lay-up process in which layers of woven material, such as laminated fiberglass, were laid over and around the structure. The laminate was thereafter impregnated with an epoxy adhesive, baked, and trimmed.
Another prior art attempt to make an improved air foil blade utilized a rubber mandrel covered with a plurality of layers of nylon mesh. The layers of nylon mesh were then epoxy coated, placed into a mold, and the entire mold was thereafter baked in an autoclave. The baked article was then split open on three sides to form a clothes pin-like member from which the rubber mandrel was removed. Next, epoxy was placed into the resulting shell and the epoxy filled member was then baked in an autoclave. The baking caused the epoxy to expand within the shell and form a foam core. The resulting blade was then balanced, sanded, shaped and painted.
Blades produced in this fashion were also found to be extremely unreliable because they would easily delaminate when chipped and would totally self destruct when such delamination was allowed to progress undetected. Delamination of any degree creates blade imbalance and erratic performance of the craft in which they were used. Further, air foil blades made in this fashion were so labor-intensive and the cost so high that only the government could afford to purchase them.
It is toward the solution of these prior art air foil blade problems by providing a novel and unique blade which enhances the reliability and safety of the aircraft in which it is used while substantially reducing of the unit cost of each blade that the present invention is directed.

Air foil blade and methods of making same


A miniature motor comprising a rotor having a plurality of magnetic poles extending axially, which is disposed radially on the outer circumferential surface of the rotor, and a stator having two coils wound on coil bobbins, which are disposed axially in a housing formed into a bottomed hollow cylindrical shape; an end plate being fitted to an open end of the housing, in which the housing is made of a ferromagnetic material, the magnetic poles are provided on a housing-side end face of the rotor so that an axial magnetic attraction force is exerted between the rotor end face and the housing.

This invention relates generally to a miniature motor, such as a stepping motor, used for printers and facsimile machines, and more particularly to a miniature motor in which only a small number of component members are required, the axial relative movement of the rotor with respect to the housing is controlled, whereby preventing mechanical noise.
Stepping motors, one type of miniature motors, have heretofore been widely used as the drive gear for information processing equipment and various other equipment. FIG. 1 is a longitudinal sectional view illustrating the essential part of an example of stepping motor of a conventional type. In FIG. 1, numeral 1 refers to a housing made of a metallic material, such as mild steel, and formed into a bottomed hollow cylindrical shape, on the inner circumferential surface of which yokes 2 made of a ferromagnetic material and formed into a ring shape, coil bobbins 3 made of an insulating material and formed into a ring shape, and coils 4 wound on the coil bobbins 3 are provided. Numeral 5 refers to an end plate to be fitted to an open end of the housing 1.
Numeral 6 refers to a rotor made of a permanent-magnet material, such as ferrite, and formed into a cylindrical shape and having a plurality of magnetic poles extending axially, which are disposed radially on the outer circumferential surface thereof. Numeral 7 refers to a shaft fixedly fitted to the center of the rotor 6 and rotatably supported by bearings 8 provided on the housing 1 and the end plate 5. Numeral 9 refers to washers made of a resin material and formed into a ring shape, and fixedly fitted to the shaft 7 in such a manner that the washers 9 are interposed between an end face of the rotor 6 and the inner end face of the housing 1, and between the other end face of the rotor 6 and the inner end face of the end plate 5. A spring washer 10 made of a metallic material having spring properties is interposed between the rotor 6 and the end plate 5 in a state that the spring washer 10 is sandwiched between two washers 11 and 12.
With the aforementioned construction, as current is fed to the coils 4 via a connector 13 and a printed-circuit board 14, the yokes 2 are excited by a combination of two-phase currents flowing in the coils 4, causing the rotor 6 having a plurality of magnetic poles disposed on the outer circumferential surface thereof to rotate in short and uniform angular movements. Thus, power is transmitted to driven equipment in accordance with the short and uniform angular movements. Since the spring washer 10 is disposed between the two washers 11 and 12, the rotor 6 is prevented from being vibrated axially and mechanical noise is therefore prevented from being generated.
However, the prior-art means having the aforementioned construction for preventing the rotor 6 from being vibrated or moved axially has the following problems. The force pushing the rotor 6 towards the washer 9 on the side of the housing 1 is dependent on the amount of axial deflection of the spring washer 10. In order to ensure the optimum amount of deflection of the spring washer 10, therefore, it is necessary to finely adjust the axial free dimensions between the washers 9 and 12 with respect to the axial dimensions between the inner end faces of the housing 1 and the end plate 5.
To this end, a plurality of washers 9, 11 and 12 having different thicknesses have to be prepared in advance. In addition, a measuring tool or inspection tool is also needed to confirm whether the spring washer 10 has the optimum amount of deflection. All this makes the assembly work of miniature motors extremely complex.
Furthermore, even after the troublesome fine adjustment described above, variability in the resiliency of the spring washer 10 cannot be avoided. Consequently, the state of mutual friction and engagement tends to be unstable among the bearing 8, the washer 9 and the rotor 6 on the side of the housing 1, and among the washer 11, the spring washer 10, the washer 12 and the end plate 5 on the side of the end plate 5. As a consequence, the resulting loss of torque also tends to be variable. This adversely affects the output torque transmitted from the shaft 7.

Miniature motor with magnetized rotor end faces forming axial magnetic attraction force between rotor and housing


A hand displaceable laser welding gun is configured with an elongated support column extending along a longitudinal axis and made from lightweight material. A support plate is displaceably mounted to the column while supporting thereon an optical head axially which is provided with optics. The optics is configured to direct a laser beam along a path towards a welding zone through a protective window of the optical head.

Field of the Disclosure
The disclosure relates to the field of hand-maneuverable welding guns for producing a seam weld and particularly to the hand-maneuverable welding gun provided with a fiber laser. Even more particular, the disclosure relates to the hand-maneuverable fiber welding gun configured with a robust, lightweight configuration, improved laser beam delivery system, effective welding debris-evacuating system and weld quality control system.
Prior Art
Welding is commonly employed as an assembly method for joining several metal parts or sheet materials together into an assembly. Conventional welding methods are readily available and include, for example, arc and resistant spot welding. Fairly recently laser welding has been developed and has provided several advantages over more conventional forms of welding. For example, the sharp focusing of the laser beam allows a concentration of energy capable of providing faster welding with less heat being introduced into the surrounding portions of the parts.
Precision automated or manual laser welding can be performed on industrial laser components with a high degree of accuracy, while eliminating the potential hazards of heat damage and thermal stress to complex manufacturing materials. The known laser spot welding and laser seam welding guns include high precision assemblies, pressure-sensitive hermetic assemblies, and other uniquely designed assemblies. Accordingly, the design of a laser welder is not simple and offers a few structural challenges, as discussed below.
One of these challenges includes welding of workpieces having a complicated geometry. For example, body panels of an automobile are transported to a welding station where a clamping system is imposed to hold the body panels while the welding operations are performed. Due to the configuration of some of the parts to be welded, certain clamping and welding apparatus cannot be utilized as space confines may limit the amount of space available for the necessary maneuvering and the proper functioning of the clamping and welding apparatus. To maximize productivity and efficiency, several different configurations of clamping and welding apparatus must be utilized within one welding station depending on the configuration, speed and cost of the clamping and welding apparatus. Such an approach may entail reduced efficiency and high costs.
A need therefore exists for a compact, lightweight, robust hand maneuverable laser welding gun having a configuration substantially eliminating the necessity of having multiple guns.
A further challenge is associated with laser configurations that are typically used for welding: CO2 and Nd:YAG. Both laser configurations operate in the infrared region of the electromagnetic radiation spectrum, invisible to the human eye.
The Nd:YAG operates at a wavelength of about 1.06 microns. This wavelength is absorbed very well by conductive materials, with a typical reflectance of about 20 to 30 percent for most metals. On the other hand, the far infrared (10.6 micron) output wavelength of the CO2 laser has an initial reflectance of about 80 percent to 90 percent for most metals but can easily supply 10,000 watts which is much greater than the highest output power of Nd:YAG lasers.
Both of the above-discussed laser types are characterized by a large physical size. For example, CO2 systems can occupy an average room to achieve the high powers required. Another commonality between these laser types is the low wall plug efficiency, i.e., low energy conversion efficiency from electrical power into optical power.
Another need, therefore, exists for a laser hand maneuverable welding gun with a laser configuration having a compact and efficient structure.
Still another challenge that was presented by known robotically operated fiber laser welders relates to the impact upon the protective window of an optical head by welding debris from the welding zone which are capable of critically damaging the optics housed in the head. To cope with this problem, a pressurized jet of air is introduced into a light guiding channel downstream from the laser head at high velocities and tangentially to the longitudinal axis of the channel. Since the jet is introduced at an angle to the light propagation, it is known as a cross-jet.
The cross jet however is also associated with a few difficulties. First, because of high velocities, the cross jet forms vortexes within the channel. The vortexes in, in turn, create a pressure gradient between the central channel zone and the channel periphery. With a pressure lower in the central zone, the welding debris accumulated along this zone and damage the protective window with a relative ease. Still a further undesirable consequence of the cross-jet is that the pressure gradient negatively affects the beam. Also, the cross jet is accompanied by high noise levels.
A further need, therefore, exists for a laser head protective system that overcomes the above-discussed problems.
Still another challenge stems from the accumulation of welding debris around a welding zone and particularly in a supporting arm of known welding systems having a two-arm clamping structure. The debris accumulation is detrimental to the quality of a weld and further damages the welder's arms.
As a result, another need exists for a laser-based hand-maneuverable welding gun configured with a system for removing welding debris from the welding zone.
A further challenge is presented by the lack of control of the quality of the weld. However the weld quality is one of, if not the most important parameter of a welding process.
Accordingly, a further need exists for a laser hand-maneuverable welding gun configured with a system for automatically adjusting laser output based on the quality of the weld.

Abstract: The laser welding gun further is structured with a first arm mounted to the support plate and extending along a longitudinal axis of the gun diametrically opposite to the optical head. The inner surface of the displaceable arm has an inner surface defining a tunnel which is aligned with the optical head and axially traversed by the laser beam, a first axially flowing stream of pressurized gaseous medium, and a second axially flowing stream of gaseous medium. The second stream, entering the tunnel at a pressure lower than that one of the first stream in response to a pressure gradient generated in the column, does not generate vortexes within the column.

Abstract: The first and second streams exit through the downstream end of the tunnel next to the welding zone. As the streams flow out, they carry out welding debris flowing within the tunnel to the optical head.


A system and method is provided for controlling an operating state of a virtual processor. An exemplary method includes determining a blocked state of a guest operating system, and, upon detecting the blocked state, determining a number of interrupt events during a first time period. If the number of interrupts is less than a first threshold or even zero during a first time period, the method includes protecting memory pages from execution by the virtual processor. Moreover, the method includes detecting, during a second time period, when the processor attempts to execute protected memory pages and unprotecting these protected memory page. Then, during a third time period, the method includes monitoring execution by the processor of the unprotected memory pages and maintaining the processor in an idle state based on the number of executed unprotected memory pages during the third time period.

In virtual machine technology, a user can create and run multiple operating environments on a server at the same time. Each operating environment, or virtual machine, requires its own operating system (OS) and can run software applications independently from the other virtual machines. Virtual machine technology provides many benefits as it can lower information technology (IT) costs through increased efficiency, flexibility and responsiveness. Each virtual machine acts as a separate environment that reduces risks and allows developers to quickly recreate different OS configurations or compare versions of applications designed for different OSs. At the same time, when many virtual machines are running on a single server, for example, it is important to maintain the virtual machines in an idle state for as much time as possible to decrease energy use and consumption of other computing system resources.
Generally, every modern (and most legacy) operating systems have a computing processing unit ("CPU") or process scheduler. During operation, the scheduler chooses a process and active threads from the process that are in a "ready to execute" state. When a new process is selected for execution, the scheduler initiates process and thread context switch to save the state of previous executed thread and then load a new thread. After the context switch, the "ready to execute" begins execution. At this point, the CPU executes code of the running thread until there is either a synchronous call to wait for some resource (or synthetic synchronization object) to be released or until there is an asynchronous hardware interrupt. For example, synchronous calls may be a Win32 API WaitForMultipleObject( ) or POSIX pthread_cond_wait( ) or other similar calls that causes the processor to enter a blocked state while it waits for some resource to be released or some conditional event to occur. Moreover, hardware interrupt events can happen, for example, as a result of some embedded device operation (e.g., a local APIC timer event, an IPI sent from one CPU to another CPU, or the like) or external peripheral device functioning (e.g., complete read operation from a hard disk).
In existing operating systems, when the process thread is in a state of waiting for some resource or condition, the thread will be moved to a "wait" state by the scheduler and the thread will remain in a blocked state until the requested resource becomes available. For a hardware interrupt, an OS interrupt handler will start execution and call a specific device driver (e.g., a kernel module extension) interrupt handler to perform the necessary interrupt processing for the device. The scheduler will then check the time quantum dedicated to the current process to ensure the time has not expired and, if so, it will pass control to the OS to return from interrupt routine to repair the interrupted thread context. However, if the time quantum has expired during the hardware interrupt event, the scheduler will push the interrupted thread from the "running" state to the "ready to execute" state in the back of the queue, select the next "ready to execute" thread, and then switch the context to the new thread.
To save energy and computing resources, the OS will normally enter an idle state when all (or most) of the processes and threads are in one of the blocked states and waiting for some condition. Usually, in hardware, this is implemented as a special processor state where the OS moves the CPU by executing a special instruction or series of instructions. For example, on the Intel IA-32, Intel 64 and AMD64 platform, a HLT ("halt") instruction is usually used for the guest OS to move the processor to the idle state. This instruction will put the processor to a low energy consumption state and will wait until some subsequent hardware interrupt happens before leaving the idle state. Sometimes this is done by a MONITOR/MWAIT instruction. Moreover, for ARM platform, the guest OS moves the processor to the idle state based on WFE or WFI instructions.
In a virtualized environment, the virtual machine monitor ("VMM") or hypervisor will emulate the corresponding instructions and place the virtual processor execution to the blocked state to wait for an emulated asynchronous event or timeout until some time-based event (e.g., an emulated timer device interrupt). One technical issue with this configuration is that the timeout for the sleep/blocked state of a virtual processor is calculated in accordance with the nearest emulated hardware time event (e.g., an interrupt of emulated PIT, local APIC timer, CMOS, or the like). Moreover, each virtual processor sleep and wake up transition takes time to execute additional state transition codes. Furthermore, when the guest OS is in a deep idle state (especially for conventional non-tickless OSs), the timer interrupt is raised only to increment certain counters, check for any unblocked processes and threads, and then pass the guest OS back to the sleep state again, by using the HLT or MONITOR/MWAIT instructions again, for example. Each transition into and out of the sleep state consumes useless time (i.e., in long sleep states without active threads) to execute guest interrupt handlers and driver codes, switcher processor states and, in case of virtualization, emulate excessive behavior.

System and method for controlling idle state of operating system


A semiconductor device and method. One embodiment provides a semiconductor substrate having a plurality of cut regions. A metal layer is located within a cut region. The metal layer includes a recess, the recess having a slit-like shape.

The invention relates to a semiconductor device and a method of manufacturing a semiconductor device, and the technology of separating a semiconductor substrate such as e.g., a wafer into semiconductor units such as e.g., chips.
Semiconductor wafers are separated into semiconductor chips for producing the same. Recently, laser dicing became increasingly attractive for various reasons, amongst them its potential to avoid cutting waste and to provide for a dry cutting process.
For these and other reasons, there is a need for the present invention.