A microwave antenna assembly is disclosed. The antenna assembly includes a feedline having an inner conductor, an outer conductor and an inner insulator disposed therebetween and a radiating portion including a dipole antenna coupled to the feedline and a trocar coupled to the dipole antenna at a distal end thereof. The antenna assembly also includes a slidable outer jacket disposed about the radiating portion and the feedline. The slidable outer jacket being configured to slide about at least one of the radiating portion and the feedline from a closed configuration, in which the slidable outer jacket is mated with the trocar and a retracted configuration, in which the slidable outer jacket is retracted in a proximally exposing at least a portion the radiating portion.

1. Technical Field
The present disclosure relates generally to microwave applicators used in tissue ablation procedures. More particularly, the present disclosure is directed to a microwave applicator having a slidable jacket that acts an electrical termination choke.
2. Background of Related Art
Treatment of certain diseases requires destruction of malignant tissue growths (e.g., tumors). It is known that tumor cells denature at elevated temperatures that are slightly lower than temperatures injurious to surrounding healthy cells. Therefore, known treatment methods, such as hyperthermia therapy, heat tumor cells to temperatures above 41° C., while maintaining adjacent healthy cells at lower temperatures to avoid irreversible cell damage. Such methods involve applying electromagnetic radiation to heat tissue and include ablation and coagulation of tissue. In particular, microwave energy is used to coagulate and/or ablate tissue to denature or kill the cancerous cells.
Microwave energy is applied via microwave ablation antenna assemblies that penetrate tissue to reach tumors. There are several types of microwave antennas, such as monopole and dipole. In monopole and dipole antennas, microwave energy radiates perpendicularly from the axis of the conductor. A monopole antenna includes a single, elongated microwave conductor. Dipole antennas may have a coaxial construction including an inner conductor and an outer conductor separated by a dielectric portion. More specifically, dipole microwave antennas are typically long, thin inner conductors that extend along a longitudinal axis of the antenna and are surrounded by an outer conductor. In certain variations, a portion or portions of the outer conductor may be selectively removed to enhance the outward radiation of energy. This type of microwave antenna construction is typically referred to as a "leaky waveguide" or "leaky coaxial" antenna.
Conventional microwave antennas tend to have a narrow operational bandwidth, a wavelength range at which optimal operational efficiency is achieved, and hence, are incapable of consistently maintaining a predetermined impedance match between the microwave delivery system (e.g., generator, cable, etc.) and the tissue surrounding the microwave antenna. More specifically, as microwave energy is applied to tissue, the dielectric constant of the tissue immediately surrounding the microwave antenna decreases as the tissue is treated. The drop causes the wavelength of the microwave energy being applied to tissue to increase beyond the bandwidth of the antenna. As a result, there is a mismatch between the bandwidth of conventional microwave antenna and the microwave energy being applied. Thus, narrow band microwave antennas tend to detune over use hindering the effective delivery and dispersion of energy.
Various improvements have been disclosed in the art, which aid in maintaining proper tuning of the antenna during use as the tissue is treated. However, these improvements tend to compromise the structural integrity of the antennas, requiring additional enhancement and/or instrumentation instruments to facilitate insertion of the antenna intro the target treatment area.


According to the present invention, an optical pickup device forms one main spot, a first subspot, and a second subspot by irradiation of light on an optical disk having a groove part and a land part. The optical pickup device includes operation circuits which indicate a deviation between each of the optical spots and a track, and α detecting means for detecting such an α value that a difference in absolute value between SPP1 and αSPP2 falls in a preset range, where an AC amplitude of a push-pull signal of the first subspot is SPP1, and an AC amplitude of a push-pull signal of the second subspot is SPP2, wherein SPP1−αSPP2 (α is a constant) is a land/groove discriminating signal. With this, in the optical pickup device for recording and reproducing information on/from the optical disk having a land/groove part, it is possible to generate a land/groove discriminating signal and a tracking error signal without an offset, thereby performing excellent tracking control.

An optical pickup must trace accurately tracks of 1.6 μm intervals in an optical disk such as a CD. Accordingly, in order to ensure stable signal detection, control at one-tenth or less a track width is required, and a control operation (tracking servo) is generally performed with a tolerance of 0.1 μm or less.
In an optical pickup device, this control operation is performed by moving an objective lens back and forth in a horizontal direction, and it is necessary to detect a signal (tracking error signal) which indicates a direction (right or left) and an amount of the movement.
Now, a three-beam method or a push/pull method has been known as a tracking servo system of an optical pickup device.
FIG. 8 is an explanatory drawing of the three-beam method. As shown in FIG. 8, a main beam SP11 is converged on an optical disk 101. On the both sides of the main beam SP11 are converged subbeams SP12 and SP13 for detecting a tracking error signal.
In this method, when the converged main beam SP11 traces accurately the track, output of the subbeam SP12 is equal to that of the subbeam SP13. On the other hand, when a tracking deviation occurs in converging the main beam SP11, output of the subbeam SP12 becomes different from that of the subbeam SP13.
Here, in the three-beam method, the tracking error signal is a differencial signal D11-D12 which is obtained from intensities D11 and D12 detected by a photodetector with respect to disk-reflected light of the respective subbeams SP12 and SP13.
However, in the three-beam method, the subbeams SP12 and SP13 to be a tracking error signal are spaced by a large distance. This causes a difference in quantity of reflected light between the subbeams SP12 and SP13 even when tracking is performed from a part where no information is recorded to a part where information is recorded in the optical disk 101 without the main beam SP11's tracking deviation, as shown in FIG. 8. Accordingly, with respect to the differential signal D11-D12, a problem arises that a tracking offset occurs due to the difference in quantity of reflected light, not due to a tracking deviation.
FIG. 9(a) and FIG. 9(b) are drawings for explaining the push-pull method. As shown in FIG. 9(a) and FIG. 9(b), the light emitted by a laser 111 is converged through an objective lens 112 onto a pit on an optical disk 113. The converged light is diffracted and reflected by the pit on the optical disk 113, and are incident on the objective lens 112 again. The reflected light incident on the objective lens 112 is incident via a beam splitter 114 on a dichotomized photodetector 115 to be detected. The dichotomized photodetector 115 has a photodetection face of two equally-divided areas and is set so that when the light beam is properly positioned with respect to the pit on the disk, two (right and left) intensities of reflected light respectively detected by the two photodetection areas become equal to each other.
Thus, if the light beam is properly positioned with respect to the pit, intensity distributions of the reflected light are indicated equally on the right and left areas of the photodetection face. That is, if the light beam is properly positioned with respect to the pit on the disk, the two photodetection areas (left and right) of the dichotomized photodetector 115 detects reflected light of equal intensity distribution. However, a deviation from the proper position causes asymmetric intensity distributions of the reflected light on the right and left areas of the dichotomized photodetector 115. That is, when the position of the light beam deviates from the pit, two (left and right) intensity distributions of reflected light detected by the two areas of the photodetection face become asymmetrical. Here, in the push-pull method, the tracking error signal is defined to be a differential signal D11′-D12′ which is obtained from detected intensities D11′ and D12′ of reflected light on the two detection areas (right and left).
However, the push-pull method has the following problem. In the push-pull method, a tracking error signal is produced by detection of a difference of light quantity distributions of reflected light from the optical disk 113 on the right side and left side of the dichotomized photodetector 115. That is, a tracking error signal is obtained by detection of a difference of intensity distributions of reflected light respectively detected on the two photodetection areas of the dichotomized photodetector 115. However, in the tracking of an optical disk, in case where the objective lens 112 moves in the radial direction, there are cases where a light axis of reflected light from the optical disk 113 shifts, and accordingly a beam center shifts from the center of the photodetection face of the dichotomized photodetector 115, as shown in FIG. 9(a). In addition, in case where a face of the optical disk 113 has a tilt, the reflected light from the optical disk 113 may return to the objective lens 112 with an angle, thereby shifting the center of the reflected light with respect to the objective lens 112, as shown in FIG. 9(b).
Thus, in both cases, there is a problem that despite no tracking deviation, a differential signal D11′-D12′ from the dichotomized photodetector 115 is offset to cause inaccurate tracking.
In light of this problem, Japanese Laid-Open Patent Publication No.45451/1999 (Tokukaihei 11-45451, published on Feb. 16, 1999) discloses a technique to solve this problem. FIG. 10(a) is a perspective view illustrating an optical pickup optical system of this conventional technology. As shown in FIG. 10(a), the light emitted from a semiconductor laser 121 is split by a first diffraction element 122 into three light beams, i.e., a zeroth-order light beam forming a main spot on an optical disk 127 and ±first-order light beams forming two subspots. Then, after passing through a second diffraction element 123, the three light beams are converted by a collimator lens 124 into parallel light beams. Furthermore, after passing through a beam splitter 125, these three light beams form on the optical disk 127 via an objective lens 126 a main spot SP21 based on the zeroth-order light beam and two subspots SP22 and SP23 based on the ±first-order light beams. After that, the three light beams are diffracted and reflected by a pit on the optical disk 127. Then, the reflected three light beams become parallel light beams again through the objective lens 126. Although these three parallel light beams pass through the beam splitter 125, these light beams are partially reflected by the beam splitter 125 and led to a magneto-optical signal detection system. The light beam led to the magneto-optical signal detection system is converted into electrical signals by elements such as an analyzer and a light receiving element for reproducing signals of the optical disk 127. Information recorded in the optical disk 127 is reproduced in this manner.
On the other hand, the other light beams having passed through the beam splitter 125 also pass through the collimator lens 124 and are diffracted by the diffraction element 123. The diffracted first-order light beam is received by light receiving elements 131 to 133 to be detected as a servo signal (focus error signal and tracking error signal, hereinafter referred to as FES and TES, respectively) and as an optical disk's land/groove (L/G) discriminating signal.
The FES is a signal for detecting a direction (upward or downward) and an amount of movement of the objective lens 126 in the focus direction. The TES is a signal for detecting a direction (right or left) and an amount of movement of the objective lens 126 in the tracking direction. Furthermore, a land means a raised part of the optical disk which defines the track. A groove means a recessed part of the optical disk which defines the track.
Next, in this optical system, the following will explain a positional relationship between the main spot SP21 and the subspots SP22 and SP23 on the optical disk 127, and light-receiving regions in the light receiving elements 131 to 133 for receiving light diffracted by the diffraction element 123.
As shown in FIG. 10(b), the main spot SP21 and the subspots SP22 and SP23 are placed symmetrically on the optical disk 127 at the intervals one-forth (P/4) of a track pitch. Note that, L represents a land, while G represents a groove. Therefore, a track pitch is a width of one land width and one groove width added together.
As shown in FIG. 11(a) through FIG. 11(c), the diffraction element 123 has divided three regions, i.e., regions 151 to 153. The diffraction element 123 is divided by a division line in the radial direction of the optical disk into two regions, i.e., the region 151 and the other region (152+153). Further, this other region is divided by a division line in the track direction of the optical disk into the regions 152 and 153.
Now, FIG. 11(a) shows a diffraction pattern SP22′ on the diffraction element 123 by reflected light from the subspot SP22 on an optical disk. In the diffraction pattern SP22′, among the diffracted light beams of the diffraction element 123, the light diffracted in the region 151 is not received. The light diffracted in the region 152 is received by a light receiving section C which is one of the divided sections of the light receiving element 131, while the light diffracted in the region 153 is received by a light receiving section D which is one of the divided sections of the light receiving element 133.
Next, FIG. 11(b) shows a diffraction pattern SP21′ on the diffraction element 123 by reflected light from the main spot SP21 on an optical disk. In the diffraction pattern SP21′, among the diffracted light beams of the diffraction element 123, the light diffracted in the region 151 is converged on the division line between light receiving sections G and H of the light receiving element 132. The light diffracted in the region 152 is received by a light receiving section E which is one of the divided sections of the light receiving element 131, while the light diffracted in the region 153 is received by a light receiving section F which is one of the divided sections of the light receiving element 133.
Furthermore, FIG. 11(c) shows a diffraction pattern SP23′ on the diffraction element 123 by reflected light from the subspot SP23 on an optical disk. In the diffraction pattern SP23′, among the diffracted light beams of the diffraction element 123, the light diffracted in the region 151 is not received. The light diffracted in the region 152 is received by a light receiving section A which is one of the divided sections of the light receiving element 131, while the light diffracted in the region 153 is received by a light receiving section B which is one of the divided sections of the light receiving element 133.
Now, when the outputs of light receiving sections A to H of the receiving elements 131 to 133 are denoted as As to Hs, respectively, servo signals are found by the following operations:FES=Gs-HsTES=(Es-Fs)−β[(As-Bs)+(Cs-Ds)]  (1)
(β is a constant)
L/G discriminating signal=(As-Bs)−(Cs-Ds)
(L/G: land/groove)
In TES, β is a constant which represents an intensity ratio of the main spot SP21 to the subspots SP22 and SP23.
However, the TES and L/G discriminating signal have the following problems.
Equation (1) finds TES by using that (As-Bs) and (Cs-Ds) are sine waves whose wavelengths are shifted by a phase angle of π/2 with respect to (Es-Fs), leading and lagging (Es-Fs), respectively, and by cancelling (Es-Fs) by a sum of (As-Bs) and (Cs-Ds).
However, as shown in FIGS. 12(a) and 12(b), each of (As-Bs), (Cs-Ds), and (Es-Fs) has a signal waveform in the form of a sine wave, with a period of track pitch P. A signal amplitude is shown as |As-Bs|<|Cs-Ds|. The following will explain the reason why a signal amplitude is shown as |As-Bs|<|Cs-Ds|. The diffraction pattern SP22′ in FIG. 11(a) and the diffraction pattern SP23′ in FIG. 11(c) are shifted away from each other in the track direction. In other words, the diffraction pattern SP22′ shifts toward upstream in the track direction relative to the diffraction pattern SP23′. With this, with respect to a beam diffraction area in the regions 152 and 153, the area of the diffraction pattern SP22′ is larger than that of the diffraction pattern SP23′. Accordingly, as a signal, the operation (Cs-Ds) of the light receiving elements 131 to 133 in FIG. 11(a) is larger than the operation (As-Bs) of the light-receiving elements 131 to 133 in FIG. 11(c). In addition, a difference in size of signals may also occur due to a sensitivity variation of thee light receiving elements 131 to 133, a variation of the diffraction element 123's diffraction efficiency, or a variation of the circuits performing the operations. Note that, as shown in FIG. 12(a), each of the signals in this case has the same offset component generated by a tilt of the optical disk, or by a change of beam spot positions on the diffraction element as a result of a shift of the objective lens.
Therefore, the operation in the second term of equation (1) for determining TES, that is,β[(As-Bs)+(Cs-Ds)]  (2),becomes |β(As-Bs)|<|β(Cs-Ds)|. As a result, as shown in FIG. 12(c), the operation result of (2) includes an additional residual offset due to the (Cs-Ds) operation component other than the tracking offset.
Therefore, in the operation of equation (1) in which the result of operation (2) is subtracted from a push-pull signal (Es-Fs) having a tracking offset due to the main beam, while it is possible to cancel an offset component generated by a tilt of the optical disk, or a variation of beam spot positions on the diffraction element as a result of a shift of the objective lens, a new Cs-Ds component is added as an additional residual offset.
As a result, as shown in FIG. 12(b), there is a problem that the additional residual offset is added to TES, and the signal phase of the TES shifts by ø from the proper signal phase, so that accurate tracking control cannot be performed.
Furthermore, the following will explain a problem caused by a tracking error signal when an adjustment error occurs in positioning subbeams on the optical disk when assembling and adjusting the pickup.
In a pickup which is designed to project the beams at the intervals of n/4 (n is odd number) of the track pitch, for example, one-forth (P/4) of the track pitch as shown in FIG. 6(a), or five-fourths (5P/4) of the track pitch as shown in FIG. 6(b), the following considers the case where positions of the subbeams are adjusted so as to be δ away from the ideal position. Here, explanations are given based on a principle of servo signal detection using the respective signal waveforms, with reference to FIGS. 13(a) through 13(c).
As shown in FIGS. 13(a) and 13(b), each of (As-Bs), (Cs-Ds), and (Es-Fs) has a signal waveform in the form of a sine wave, with a period of track pitch P. Here, (As-Bs) and (Cs-Ds) in the second term of equation (1) for determining TES have signal amplitudes different from that of the ideal waveform and have a phase difference of ±γ with respect to the ideal waveform, as shown in FIG. 13(a).
As a result, the operation result ofβ[(As-Bs)+(Cs-Ds)]  (2)includes a residual offset which is out of phase from (Es-Fs) as shown in FIG. 13(c).
As a result, there is a problem that the residual offset is added to the TES, and the signal phase of the TES is out of phase by øb from the ideal TES phase, so that accurate tracking control cannot performed.
Furthermore, the L/G discriminating signal is found by the operation of (As-Bs) and (Cs-Ds). However, since (As-Bs) and (Cs-Ds) are out of phase, as shown in FIG. 13(c), the phase of the L/G discriminating signal is out of phase by øc from the ideal discriminating signal, so that accurate land/groove discrimination cannot be performed. Accordingly, the tracking servo system cannot perform a pull-in operation.
Incidentally, the residual offset tends to become larger as the adjustment error becomes large in positioning subbeams on the optical disk when assembling and adjusting the pickup. Therefore, conventional pickups must be assembled so that an adjustment error in positioning subbeams becomes as small as possible. This means greater difficulties in assembling and lower yield, resulting in rise in manufacturing cost.


Embodiments of the present invention provide a liquid crystal display device and a producing method thereof, and relate to the field of liquid crystal display. The liquid crystal display device of the present invention comprises a liquid crystal panel and a first optical compensation structure and a second optical compensation structure located at two sides of the liquid crystal panel, and the second optical compensation structure comprises: a polarizing film layer, a compensation film layer and a biaxial film layer, wherein, the polarizing film layer is located between the compensation film layer and the biaxial film layer; and the biaxial film layer is located between the polarizing film layer and the liquid crystal panel. Through providing the biaxial film layer in the second optical compensation structure, the present invention can effectively correct the color shift generated in the diagonal direction of the liquid crystal panel and improve the product quality.

With the continuous development of LCD (Liquid Crystal Display) display technologies, people have continuously increasing demands on the quality of the LCD. An IPS (In-Plane Switching) type LCD with a higher contrast and wider visible view angle has been more and more popular with people.
Being different from a TN (Twisted Nematic) type liquid crystal display, the liquid crystal of the IPS type liquid crystal display is applied with a horizontal electric field, and then the liquid crystal molecules can conduct twisted movement within a plane parallel to a substrate. The twisting of the liquid crystal molecules will change the travelling direction of light. In order to increase the contrast of the liquid crystal display, the current IPS type liquid crystal display needs to dispose equivalent polarizers at two sides of a liquid crystal panel. The structure of the IPS type liquid crystal display in the prior art is shown in FIG. 1, and the liquid crystal display comprises an upper optical compensation structure 11 having a polarizing function, a liquid crystal panel 12 and a lower optical compensation structure 13 arranged opposite to the upper optical compensation structure 11. The upper optical compensation structure 11 further comprises a first TAC layer 111 and a second TAC layer 113 having a polarizing effect and an optical compensation function, and a first PVA layer 112 as a polarizing film layer which is located between the first TAC layer 111 and the second TAC layer 113, a third TAC layer 131, a second PVA layer 132 and a fourth TAC layer 133 contained in the lower optical compensation structure 13 correspond to the second TAC layer 113, the first PVA layer 112 and the first TAC layer 111 of the upper optical compensation structure 11, respectively, and the hierarchical structure relationship among the respective layers is shown in FIG. 1. The IPS type liquid crystal display with this structure has a disadvantage that color shift may occur in the diagonal direction of the liquid crystal panel. Taking the IPS type liquid crystal display shown in FIG. 1 as an example, the Δnd of the current liquid crystal panel 12 is usually 392.7 nm, the horizontal phase differences Re of the second TAC layer 113 and the third TAC layer 131 are both 3 nm, and their thickness direction phase differences Rth are both 40 nm, and thus generated color shift in the diagonal direction is shown in FIG. 2. The prior art cannot solve the problem of color shift generated in the diagonal direction of the liquid crystal panel.

Liquid crystal display device and method for manufacturing the same

Hefei BOE Optoelectronics Technology Co., Ltd.


To provide an optical image measuring apparatus capable of calculating an intensity of a direct current component composed of background light based on a result obtained by detection of interference light and obtaining a signal intensity of the interference light using the calculated intensity. The apparatus includes: an optical interference system to divide a light beam into signal light and reference light, and the signal light propagating through an object to be measured and the reference light are superimposed to produce interference light; beam splitters for dividing it into three interference light beams; shutters to perform sampling; photo detectors for detecting the sampled interference light beams and converting them into electrical signals; and a signal processing portion for calculating the signal intensity of the interference light and the spatial phase distribution thereof based on the electrical signals.

1. Field of the Invention
The present invention relates to an optical image measuring apparatus employing a structure in which an object to be measured which is particularly a light scattering medium is irradiated with a light beam and a surface form or inner form of the object to be measured is measured based on a reflected light beam or a transmitted light beam to produce an image of a measured form. More particularly, the present invention relates to an optical image measuring apparatus for measuring the surface form or inner form of the object to be measured by using an optical heterodyne detection method to produce the image of the measured form.
2. Description of the Related Art
In recent years, attention has been given to optical imaging techniques for producing an image of a surface or inner portion of an object to be measured using a laser light source or the like. In contrast to the conventional X-ray CT technique, optical imaging technique is not hazardous to human bodies. Therefore, its application to the field of biomedical imaging is highly desired.
An example of a typical method of the optical imaging technique is a low coherent interference method (also called "optical coherent tomography" or the like). This method uses the low coherence of a broad band light source having a wide spectral width, such as a super luminescent diode (SLD). According to this method, reflection light from an object to be measured or light transmitting therethrough can be detected with a superior distance resolution of μm order (for example, see Naohiro Tanno, Kogaku (Japanese Journal of Optics), Volume 28, No. 3, 116 (1999)).
FIG. 6 shows a fundamental structure of a conventional optical image measuring apparatus based on a Michelson interferometer, serving as an example of an apparatus using the low coherent interference method. An optical image measuring apparatus 100 includes a wide band light source 101, a mirror 102, a beam splitter (half mirror) 103, and a photo detector 104. An object to be measured 105 is made of a scattering medium. A light beam from the broad band light source 101 is divided by the beam splitter 103 into two parts, that is, a reference light R propagating to the mirror 102 and a signal light S propagating to the object to be measured 105. The reference light R is a light beam reflected by the beam splitter 103. The signal light S is a light beam transmitting through the beam splitter 103.
Here, as shown in FIG. 6, the propagating direction of the signal light S is set as a z-axis and a plane orthogonal to the propagating direction of the signal light S is defined as an x-y plane. The mirror 102 is shiftable in both of the forward and backward direction, as indicated by a double-headed arrow in FIG. 6 (z-scanning direction).
The reference light R is subjected to a Doppler frequency shift by z-scanning when it is reflected on the mirror 102. On the other hand, the signal light S is reflected from the surface of the object to be measured 105 and from the inner layers thereof when the object to be measured 105 is irradiated with the light. Because the object to be measured 105 is a scattering medium, the signal light S reflected from the object may include the multiple scattered light waves having random phases. The signal light reflected from the object to be measured 105 and the reference light reflected from the mirror 102 to be subjected to the frequency shift are superimposed on each other by the beam splitter 103 to produce an interference light.
In the image measurement using the low coherent interference method, interference occurs only when a difference in optical path length between the signal light S and the reference light R is within the coherent length, of the broad band light source 101, which is of the order of several μm to tens of μm. In addition, only the component of the signal light S where phase is correlated to that of the reference light R may interfere with the reference light R. That is, only the coherent signal light component of the signal light S selectively interferes with the reference light R. Based on these principles, the position of the mirror 102 is shifted by the z-scanning operation to vary the optical path length of the reference light R, so that a light reflection profile of the inner layers of the object to be measured 105 is measured. The interference light is detected by the photo detector 104 during each z-scan. An electrical signal (heterodyne signal) output from the photo detector 104 provides a backscatter profile of the inner layers of object to be measured 105, and a two-dimensional cross-sectional image of the object to be measured 105 is produced by scanning the signal lights S across the object to be measured 105 while recording the reflectance profile at each transverse position (see Naohiro Tanno, Kogaku (Japanese Journal of optics), Volume 28, No. 3, 116 (1999)).
Assume that an intensity of the reference light R and an intensity of the signal light S which are superimposed by the beam splitter 103 are given by Ir and Is, respectively, and a frequency difference between the reference light R and the signal light S and a phase difference therebetween are given by fif and Δθ, respectively. In this case, a heterodyne signal as expressed by the following expression is outputted from the photo detector (for example, Yoshizawa and Seta "Optical Heterodyne Technology (revised edition)", New Technology Communications (2003), p. 2).i(t)∝Ir+Is+2√{square root over (IrIs)} cos(2πfift+Δθ)   (1)
The third term of the right side of the expression (1) indicates an alternating current electrical signal and the frequency fif thereof is equal to the frequency difference between the reference light R and the signal light S. The frequency fif of an alternating current component of the heterodyne signal is called a beat frequency or the like. The first and second terms of the right side of the expression (1) indicate the direct current components of the heterodyne signal and correspond to the background light intensity.
However, when the two-dimensional cross-sectional image is intended to be obtained by means of the conventional low coherent interference method, it is necessary to scan the signal light beam S across the object to be measured 105 and to successively detect reflection light waves from each transverse position. Therefore, the measurement of the object to be measured 105 can be time consuming. In addition, it is hard to shorten a measurement time in view of measurement fundamentals.
In views of such problems, an optical image measuring apparatus for shortening a measurement time has been proposed. FIG. 7 shows a fundamental structure of an example of such an apparatus. As shown in FIG. 7, an optical image measuring apparatus 200 includes a broad band light source 201, a mirror 202, a beam splitter (half mirror) 203, a two-dimensional photo sensor array 204 serving for light detection, and lenses 206 and 207. Alight beam from the light source 201 is converted into a parallel light flux by the lenses 206 and 207 and a beam diameter thereof is increased thereby. Then, the parallel light flux is divided by the beam splitter 203 into two, that is, the reference light R and the signal light S. The reference light R is subjected to a Doppler frequency shift by z-scanning of the mirror 202. On the other hand, the signal light S is incident on the object to be measured 205 over a wide area of the x-y plane, as a consequence of a widened beam diameter. Therefore, the signal light S reflected from the object to be measured 205 contains information related to the surface and inner portion of the object to be measured 205 over a wide area. The reference light R and the signal light S are superimposed on each other by the beam splitter 103 and detected by the elements (photo sensors) arranged in parallel on the surface of the two-dimensional photo sensor array 204. Thus, it is possible to obtain a two-dimensional cross-sectional image of the object to be measured 205 in real time without scanning the signal lights.
An apparatus described by K. P. Chan, M. Yamada, and H. Inaba in Electronics Letters, Vol. 30, 1753 (1994) has been known as such a non-scanning type optical image measuring apparatus. In the apparatus described in the same document, a plurality of heterodyne signals outputted from a two-dimensional photo sensor array are inputted to signal processing systems arranged in parallel to detect the amplitude and phase of each of the heterodyne signals.
However, when spatial resolution of an image is intended to be improved, it is necessary to increase the number of elements of the array. In addition, it is necessary to prepare a signal processing system including the number of channels corresponding to the number of elements. Therefore, it is likely to be hard to actually use the apparatus in fields that require a high-resolution image, such as a medical field and an industrial field.
Thus, the inventors of the present invention proposed the following non-scanning type optical image measuring apparatus in JP 2001-330558 A (claims, specification paragraphs [0068] to [0084], FIGS. 1 and 3). The optical image measuring apparatus according to the present proposal includes a light source for emitting a light beam, an interference optical system, and a signal processing portion. In the interference optical system, the light beam emitted from the light source is divided into two, that is, a signal light propagating through an examined object locating position in which an object to be examined is located, and a reference light propagating along an optical path different from an optical path passing through the examined object locating position. The signal light propagating through the examined object locating position and the reference light propagating along a different optical path are superimposed on each other to produce the interference light. The interference optical system includes a frequency shifter, light cutoff devices, and photo sensors. The frequency shifter shifts a frequency of the signal light and a frequency of the reference light relative to each other. In order to receive the interference light in the interference optical system, the interference light is divided into two parts. The light cutoff devices periodically cut off the two divided parts of the interference light to generate two interference light pulse trains with a phase difference of 90 degrees therebetween. The photo sensors respectively receive the two interference light pulse trains. The photo sensors each have a plurality of light receiving elements which are spatially arranged and each of which separately obtains a light receiving signal. The signal processing portion combines a plurality of light receiving signals obtained by each of the photo sensors to generate signals of the signal light which correspond to respective points of interest of a surface or inner layers of the object to be examined which is located in the examined object locating position on a propagation path of the signal light.
In the optical image measuring apparatus, the interference light in which the reference light and the signal light interfere with each other is divided into two parts and the two parts of the interference light are received by the two photo sensors (two-dimensional photo sensor arrays) and respectively sampled by the light cutoff devices disposed in fronts of both sensor arrays. A phase difference of π/2 is provided between sampling periods of the two divided parts of the interference light. Therefore, an intensity of the signal light and an intensity of reference light which compose background light of the interference light and phase quadrature components (sine component and cosine component) of the interference light are detected. In addition, an intensity of the background light included in the outputs from both the sensor arrays is subtracted from the outputs of both the sensor arrays to calculate two phase quadrature components of the interference light. An amplitude of the interference light is obtained based on a result obtained by calculation.
In the case of measurement using the optical image measuring apparatus described in JP 2001-330558 A, it is necessary to measure and obtain an intensity of a direct current component corresponding to the background light of the interference light included in the outputs from the two-dimensional photo sensor arrays in advance. Therefore, when the intensity of the direct current component can be measured, the availability of the measurement is shown. However, in the case where it is hard to measure the intensity of the direct current component corresponding to the background light, such as the case where an object to be measured, a part thereof, or an inner portion thereof is moving, it is difficult to measure the object to be measured using the optical image measuring apparatus.
An available image sensor such as a CCD (charge-coupled device) camera has been widely known as the two-dimensional photo sensor array of the optical image measuring apparatus. However, up to now, a problem has been recognized in that a currently available CCD camera cannot follow a beat frequency of a heterodyne signal which is of the order of several kHz to several MHz because of a low frequency response characteristic. The feature of the optical image measuring apparatus which is proposed by the inventors of the present invention and described in JP 2001-330558 A is that the measurement is performed using the low frequency response characteristic to advantage based on the sufficient recognition of the problem.

Optical image measuring apparatus for obtaining a signal intensity and spatial phase distribution of interference light


A method and communication network wherein one or more announcement texts are established in a service control point. A message initiated on the basis of a call of the subscriber wherein information about the supportability of announcements by an announcement unit are contained is received and interpreted by the service control point. Given support of an announcement by an announcement unit, a message in which the announcement text is contained is sent from the service control point. The announcement unit converts a received announcement text into an announcement that is then transmitted to the calling subscriber on a voice channel.

Field of the Invention
The present invention relates to the support of additional services for subscribers of a communication network, such as a fixed network or a mobile radio telephone network, through the use of an intelligent network with service control points.
Communication networks, for example fixed networks or mobile radio telephone networks constructed in the fashion of the known GSM mobile radio telephone network (global system for mobile communications), include switching equipment networked with another. Respective base stations, with whose assistance communication terminals can be connected via an air interface, are connected to the switching equipment in the mobile radio telephone network. In the fixed network, the communication terminal equipment is connected to the switching equipment via lines. The communication terminal equipment thus enables a subscriber to have network access independently of the network type. The switching equipment, over and above this, can effect a transition to further networks, for example data transmission networks, fixed networks or mobile radio telephone networks. In the GSM mobile radio telephone network, memory units wherein, among other things, subscriber-specific data for network-proper services are stored, are employed. One of these memory units is the home register that is usually located at a permanently defined location wherein the data underlying the registration of the subscriber is deposited. Dependent on the momentary location of the mobile subscriber, at least one further memory unit-the visitor register-is responsible. Dependent on the location of the mobile subscriber, the responsibility of determining which memory unit, having specific data stored for this subscriber, is to surface can change via the subscriber.
It is well known to support additional services for the subscribers of a communication network either a fixed network or mobile radio telephone network, by the structure of an intelligent network with service control points. These service control points and the profiles of the additional services deposited therein, including the information needed for their implementation can be modified independently of the respective communication network. The services useable in an intelligent network are thereby initiated in a service switching point in order to effect a departure from the standard call processing and activate the access to the additional services. One of such services is that of making one or more announcements available to the subscriber of the communication network. This is achieved in that the announcement is initiated by a service switching point and is implemented by an announcement unit connected thereto (intelligent peripheral). The selection of the announcement occurs with a service control point via an INAP signaling (intelligent network application part). What is disadvantageous about the method is that all announcements must be pre-defined in the announcement unit; i.e., the announcements proceeding must be previously registered and loaded into the announcement unit. This procedure is inflexible with respect to offering and producing new announcements, since these must be registered xe2x80x9cofflinexe2x80x9d and stored in the announcement unit before use thereof is possible. Over and above this, an announcement identification, for example with an announcement telephone number, must be offered and signaled for the selection of the respective announcement. The corresponding announcement identifications are to be declared between the service control point and service switching point in order to be able to use the new announcements.
U.S. Pat. No. 5,592,535 discloses a method and arrangement for billing call connections upon utilization of the equipment of an intelligent network. The mobile subscriber of a mobile radiotelephone network thereby has a credit account whose current line of credit is compared to a prescribable minimum threshold given a call by the subscriber. The implementation of the call connection only occurs when the credit line lies above this threshold. By involving the equipment of the intelligent network, the appertaining INAP protocol (Intelligent Network Application Protocol) can be applied instead of the MAP protocol (Mobile Application Protocol).
U.S. Pat. No. 5,594,789 discloses a multimedia communication system with equipment of an intelligent network whereof an intelligent system means includes a speech recognition unit as well as a speech verification unit. The multimedia system utilizes the speech recognition and speech verification for connection control and, in particular, for the implementation of a transaction, whereby the service control point includes a specific database for the identification of a speech sample which a subscriber inputs into a terminal or into a telephone for authentification purposes. When the comparison of the speech sample to an entry stored in the database yields identity, the transaction is implemented. xe2x80x9cThe CAMEL feature, proposed revisions to the stage 1 descriptionxe2x80x9d of ETSI/STC/SMG1, Mar. 14, 1995, GSM 02.78, Version 0.4.0, pages 1 through 14, discloses a CAMEL (customized application for mobile network enhanced logic) platform with which the support of additional vendor-specific services should be enabled for subscribers, for example, even when they are residing abroad. An operator-specific, additional service thus can be used beyond network and service boundaries of a communication network. This is the case when the service switching unit initiating the additional service can process the required CAP signaling (CAMEL application part) for the requested service and when signaling information from and to the home register and to the service control unit of the additional service can be exchanged beyond the network boundaries. What this means for the announcement is that, when a mobile subscriber resides in a network other than the home network, the announcements of all other networks must be known there and must be unambiguously identifiable. This incurs a high handshaking outlay that must occur across network boundaries and that is relatively. A solution via xe2x80x9creroutingxe2x80x9d from the network in which the subscriber resides to his home network in order to set up the announcement there would lead to an additional occupation of lines and, thus, would require additional transmission resources.
The present invention is therefore directed to an optimally flexible method and a corresponding communication network for offering announcements for the subscribers.
The inventive method for offering announcements therefore provides that one or more announcement texts are established in a service control point. A message initiated on the basis of a call by a subscriber, wherein information about the supportability of announcements by an announcement unit are contained, is received and interpreted by the service control point. Given the support of an announcement by an announcement unit, a message in which the announcement text is contained is sent from the service control point to the announcement unit. The announcement unit converts the received announcement text into an announcement that is then transmitted to the calling subscriber on a voice channel.
The advantage of the inventive method is that only the announcement texts are introduced in a service control pointxe2x80x94that is usually arranged at a center locationxe2x80x94and the announcements themselves are set up by the announcement units by converting the received announcement texts. The central storing of announcement texts avoids a complicated handshaking of the announcements between service control point and service switching point or respectively, announcement unit via a corresponding signaling. Further, it enables a fast and flexible adaptation of announcement unit via a corresponding signaling and enables a fast and flexible adaptation of announcements to new services and service expansions. The enhanced flexibility leads to cost-savings since the announcement units no longer are to be reloaded given every change or addition of an announcement. The offering of the announcements also occurs independent of location without the announcements having to be previously pre-defined in the respective announcement units. The outlay for introducing new announcements is, thus, substantially reduced. Offering the announcements according to the CAMEL platform for a xe2x80x9croamingxe2x80x9d subscriber beyond network boundaries is significantly simpler due to the inventive procedurexe2x80x94less outlay for signaling and line occupancy. The announcements are made available to the subscriber on site both in his own network as well as in an outside network, for example, abroad, by simply converting the received announcement texts. The advantage for him is that the announcements are recorded in a language he can understand, preferably in his native language.
The inventive method can be applied to fixed networks as well as mobile radio telephone networks given that the announcement is played for the calling subscriber via a voice channel controlled by a service control point and supported by an announcement unit. Another advantage of the inventive method is that one is able to transmit the information about the supportability of announcements and the announcement text or texts in messages that are part of the IANP or, respectively, CAP signaling. This means that no outlay for additional lines or signaling messages is required for the inventive method.
The communication network according to the present invention is characterized in that one or more announcement texts are established in the service control point. A message initiated due to a call of the subscriber, wherein information about the supportability of announcements by an announcement unit are contained, is received and evaluated by the service control point. When an announcement is supported by an announcement unit, a message wherein the announcement text is contained is sent from the service control point to the announcement unit. The announcement unit converts a received announcement text into an announcement that is then transmitted to the calling subscriber on a voice channel.
A service control point for supporting the present invention includes means for storing one or more announcement texts as well as means for storing and evaluating a message initiated on the basis of a call of the subscriber wherein information about the supportability of announcements by an announcement unit are contained. Over and above this, the service switching point is provided with means for transmitting a message wherein the announcement text is transmitted to an announcement unit supporting the announcement, the received announcement text being converted into an announcement by the latter, this announcement then being transmitted to the calling subscriber on a voice channel via a service switching point.
A service switching point for supporting of the present invention includes means for the reception of the message wherein the announcement text is contained and further includes means for transmitting the announcement text to an announcement unit that supports the announcement. The received announcement text is then converted by the announcement unit into an announcement that is transmitted to the calling subscriber on a voice channel via a service switching point.
An announcement unit for supporting the present invention includes means for the reception of the message wherein an announcement text is contained and further includes means for converting the announcement text into an announcement that is then transmitted to the calling subscriber on a voice channel via a service switching point.
Additional features and advantages of the present invention are described in, and will be apparent from, the Detailed Description of the Preferred Embodiments and the Drawing.

Method and communication network for offering announcements


The embodiment disclosed herein relates to systems and methods to provide improvements to power delivery systems employed with lamps in general and fluorescent lamps in particular. In accordance with one exemplary embodiment, cathode current is controlled to a maximum level to quickly bring the cathode temperature up to thermionic emission temperature. After lamp ignition, a cathode voltage reduction circuit is employed to reduce voltage of the external cathode heating. Power is supplied to a power factor correction circuit via an IC, in accordance with a second exemplary embodiment. Finally, a third disclosed embodiment addresses desensitizing the lamp from various deleterious parasitic capacitive effects associated with the power delivery to one or more lamps.

Generally, there are two types of ballasts employed in today's fluorescent lamps; programmed start ballasts and instant start electronic ballasts. Typically, a program start electronic ballast provides a relatively low voltage across the lamp with a separate cathode heating current during lamp startup. Pre-heating the cathode before lamp ignition lowers the amount of voltage needed to strike the lamp, that is, the glow discharge current is minimized. By minimizing the glow discharge current, the cathode life is extended since the amount of the cathode that is spattering off during lamp startup is minimized, extending the overall life of the lamp.
This type of lighting system finds particularly useful application in a setting where the lights are frequently turned on and off, such as in a conference room, a lavatory, or other setting that sees frequent but non-continuous usage. In these settings, light is needed when the room is in use, but typically the lights are turned off to save energy when no one is using the room. In short, the program start electronic ballast is beneficial for applications in which the lamps undergo a high number of on/off cycles.
Despite its advantages, the program start electronic ballast does have drawbacks. First, because it has to pre-heat the cathode before it strikes the lamp, there is a noticeable delay from the time when the light switch is activated to the time when the lamp emits visible light. Typically this delay is on the order of 1.5 seconds. This delay can be referred to as preheat or waiting time and is a disadvantage in settings where a user expects an almost instantaneous lighting of an area.
Another drawback of the program start lamp ballasts is that they are commonly utilized in a series lamp configuration. In a series configuration, if one lamp fails, it will shut down the circuit for the whole ballast, causing all lamps in the ballast to be turned off. Thus, the lamps in the ballast produce no light where they could be producing light from other lamps if the lamps were in a parallel configuration. Since all lamps will not be producing light, more frequent servicing of the lighting installation will be required, increasing the cost of labor to maintain the system.
Yet another disadvantage to the program start ballast is when lamp current is low (e.g., below 160 mA), external cathode heating can be required in order to maintain the rated lamp's life. Conventional program start ballast configurations do not address this issue of optimizing cathode heating for both preheat and operation which can minimize start time and provide energy savings.
The second conventional type of ballast, the instant start ballast, addresses some issues of the program start ballast, however, it introduces some new issues of its own. Typically, an instant start ballast does not pre-heat the cathodes, rather it applies the operating voltage directly to the lamp. In this design, at the moment the switch is turned on, a high voltage is provided across the lamp. For a typical system, the voltage can be about 600 V, and the peak voltage can be up to about 1000 V. With this high voltage across the lamp, sufficient glow current exists to bring the lamp up to a point where the lamp will ignite quickly. The lamp, therefore, has a much shorter ignition time (typically about 0.1 seconds) as compared to the program start systems, and light is seen substantially concurrently with the activation of the light switch. Also, there is no extra current drain to the cathodes during operation, since the operating voltage is applied directly to the lamp cathodes. Instant start ballasts also use parallel lamp configurations with inherently built-in redundancy in the event of the lamp failure.
However, the instant start ballast produces a glow discharge current, which degrades the integrity of the cathodes during the brief period before the lamp strikes. Over time, with instant start ballasts, the cathodes degrade at a rate, leading to an early failure of the lamp. Thus, a drawback of the instant start ballast is premature lamp failure. Because an instant start ballast burns through cathodes so quickly, lamps may fail long before their expected lifetimes.
While the program start ballasts are inefficient because they waste power, the instant start ballasts are inefficient because they may require more lamps for a given amount of time. Consequently, it is desirable to take the advantages of the beneficial aspects of the program start ballast (e.g., longer lamp life) and combine them with the advantages of the instant start ballast (e.g., quick start time) to produce an improved lamp ballast. The present application contemplates a method and apparatus that combines the positive aspects of the program start and instant start ballasts without propagating the negative aspects of those ballasts.

Method of controlling cathode voltage with low lamp's arc current


A car radio with an electronic anti-theft device, which device includes circuitry for electrically detecting the removal of the car radio from its build-in recess, and by which the function of the car radio is blocked as long as the anti-theft device is not deactivated after the removal. A simple arrangement with a highly reliable mode of operation is obtained in that the circuitry for electrically detecting the removal of the car radio includes a monitoring circuit, by which the presence of a connection from the car radio to at least one loudspeaker is monitored continuously, and by which the anti-theft device is activated immediately after the interruption of this connection.

1. Field of the Invention
The invention relates to a car radio with an electronic anti-theft device, which device comprises means for electrically detecting the removal of the car radio from its build-in location, and by which the function of the car radio is blocked as long as the anti-theft deice is not deactivated after the removal.
2. Description of the Related Art
German Patent DE-PS 37 17 054, corresponding to U.S. Pat. No. 4,808,981, is known a car radio with an electronic anti-theft device, this device comprising a memory for a codeword, means for entering the codeword, as well as means for electrically detecting a removal of the car radio from its build-in location, means blocking the functioning of the car radio as long as the codeword is not entered after the removal. To create a purely electronic anti-theft device which can neither be outwitted with an additionally connected battery, nor requires the use of an electronic key activating the circuit arrangement, the known car radio comprises a circuit arrangement which measures the impedance on at least one connecting terminal of the car radio when the device is switched on, compares the measured impedance value to the stored impedance value established previously at the build-in location and, when different values occur, blocks the functioning of the car radio until the right codeword is entered. Preferably, the impedance measurement is made on at least one loudspeaker terminal, while a signal generated in an AC voltage generator is applied to the loudspeaker terminal via a switch to measure the impedance. The impedance value on the loudspeaker terminal is then determined on the basis of the measured voltage on the loudspeaker terminal and on the basis of the AC current flowing through the loudspeaker circuit.
The codeword is to be entered in this car radio after it is built in and, simultaneously, the impedance value present on the loudspeaker terminal is to be entered in the memory as a digital value. For this purpose, the impedance value determined with said circuit arrangement is applied via an A/D converter to a microprocessor and written in the memory by this microprocessor. When the car radio is put in operation again, the microprocessor compares the impedance value present on the loudspeaker terminal to the impedance value stored in the memory when the car radio was put in operation for the first time. If the two values match, the car radio starts operating. If the two values do not match, the functioning of the car radio is blocked and the user is requested to enter the codeword. In the case of an authorized removal of the car radio from the vehicle, the entry of the codeword thus makes it possible to have the car radio operate again even, for example, with different loudspeakers.
Apart from a substantial cost of circuitry for the impedance measurement, the storing of the measured impedance values and the comparison of a newly measured impedance value to the stored impedance value shows that this anti-theft device does not provide a satisfactory protective function either. In the case of unauthorized removal of the car radio, it is possible to circumvent the compulsion of entering the codeword if, prior to the renewed, this time unauthorized operation, for example, loudspeakers are connected whose electrical characteristic values correspond to those from the vehicle of the authorized user. Such a circumvention of the anti-theft device may be facilitated in that, for example, the impedance values of loudspeakers for car radios are standardized. In order to avoid such a circumvention of the anti-theft device, a high-resolution impedance value should be determined by means of an accordingly high-cost impedance measurement. However, this may lead to the fact that already existing different transfer resistances on the connecting terminal, lead to the anti-theft device also being triggered by the authorized user. This also makes it difficult for the authorized user to handle the car radio; more particularly, the handling is affected by variations of the physical parameters which are inestimable for him.
In this case, the car radio described in DE-PS 37 17 054 does not have an advantage compared with the car radio in which, basically, after each disconnection, for example, from the battery of the motor vehicle, the codeword is required to be entered. But also a blocking of the car radio, when the operating voltage from the battery of the motor vehicle is interrupted, is hardly advantageous despite its simple realization, because it is useless in the cases where the car radio is stolen with connected voltage supply. Furthermore, it has appeared that the blocking of the above type causes problems, for example, during so-called start or load dump operations. By storing the voltage in capacitors inside the car radio, it is also possible to slow down the activation of the anti-theft device, i.e., the blocking of the car radio, so that in certain cases, the activation can be disturbed or prevented or is disturbed, respectively.


A bullet with grooves to create more surface area to reduce drag, thus keeping a flatter trajectory that reduces the effects of wind, temperature, elevation and angle. Groves would be manufactured into the bullet and bullet jacket twist would need to match the barrel twist. For example, 1 in 8 twist, 1 in 8½ twist, 1 in 9 twist, 1 in 10 twist, 1 in 11 twist etc. Groves would be over the ogive of the bullet prior to where the bullet contacts the barrel wall.

A bullet is the projectile expelled from a firearm during firing. To optimize accuracy and distance a bullet must balance internal ballistics (forces inside the gun) and external ballistics (forces acting on the bullet after leaving the muzzle of a gun). A projectile shot from a gun tends to tumble through the air. Bullet spin, ie stabilization, stabilizes the orientation of the projectile in flight. However, stabilization must be balanced: overstabilized bullets and understabilized bullets are less accurate than correctly stabilized bullets. However, under current systems and methods, projectile spin only occurs while the bullet is in contact with bore rifling. Therefore a need exists to correctly stabilize the bullet outside the bore.

Systems and methods for matching ogive twist and barrel twist


The present invention relates to a process for manufacturing recyclable black enamels that contain at least zinc, in which process glass forming materials comprising at least bismuth, silicon, boron and manganese are melted, at temperatures greater than about 900xc2x0 C., and then a glass frit comprising at least zinc is added to the mixture obtained after this direct melting. The invention also relates to zinc-based recyclable black enamel compositions.

The present invention relates to the deposition of enamel on a glass substrate, especially on glazing. In particular, it relates to a novel enamel composition and to the process for obtaining it, a process for manufacturing an enamelled layer on a glass substrate, and the enamelled products obtained, particularly enamelled glazing.
Enamels are well known in the prior art and are used, especially, for coating glass substrates, such as glazing in the motor-vehicle industry or the building industry. They make it possible to form decorative layers or inscriptions, conductive layers, protective layers, especially layers for protecting the adhesive layers or adhesive beads intended for mounting glazing in body openings from ultraviolet radiation, masks, especially masks for concealing current-collecting strips of heating grids or for concealing the above mentioned adhesive beads and similar products.
Before application to the substrate and firing, these enamels used for coating glass substrates are generally formed from a powder comprising a glass frit, which is included to provide a glassy matrix, and pigments, which are used as colorants. The pigments also possibly form part of the frit. Both the frit and the pigments are generally based on metal oxides. Also, a medium or xe2x80x9cvehiclexe2x80x9d is used to allow application and temporary adhesion of the enamel to a substrate. The medium, chosen according to the intended use of the enamel, must ensure that the particles of the frits and pigments used are properly in suspension and must be consumed at the latest during firing of the enamel. This medium may include solvents, diluents, oils, resins and the like.
One problem with existing enamelled glass substrates is the difficulty of recycling such products, particularly in the manufacture of glass substrates in the form of sheets or glazings. Since such products must meet many requirements in terms of coloration, light and/or energy transmission, etc., it is important in fact that the glass waste reintroduced in ground form or cullet into the melting furnaces used for manufacturing new glazings does not disturb the glass compositions normally already present and does not give products that do not meet the necessary requirements. Although non-enamelled glass cullet can thus be reintroduced into a furnace for manufacturing float glass in amounts generally of about 20-30% by weight of the charge of the furnace, enamelled glass cullet, on the other hand, generally causes the appearance of undesirable residual colorations or of residual unmelted islands in the glass sheets formed. Consequently, the amount of enamelled glass cullet that can be reintroduced into these furnaces does not generally exceed 2 to 3% by weight of the charge of the furnaces. Usually, the enamelled glass cullet constitutes from 0.1 to 0.5% by weight of the charge.
An improved enamel composition and an enamelling process are already known from WO 98/25864, which makes it possible to obtain improved enamelled glass substrates, particularly enamelled substrates which can be recycled (especially in the manufacture of glazing) more easily than the existing enamelled substrates. This composition comprises as pigments one or more manganese compounds and has a firing temperature, also called melting point, of less than 750xc2x0 C. In motor-vehicle applications, the composition is preferably chosen so as to obtain a black enamel having the following colorimetric coordinates, in absolute values:
L*xe2x89xa65; |a*|2 and |b*|xe2x89xa62 (and, preferably,
|a*|xe2x89xa61 and |b*|xe2x89xa61).
This is generally the case in the compositions described in the above document, which essentially comprise Bi2O3 as intermediate oxide. They are obtained either by adding the manganese compounds in the form of powder to a glass frit powder including Bi2O3, or by a process, called the xe2x80x9cdirect process,xe2x80x9d by melting a mixture of suitable raw materials (including the manganese compounds) in order to obtain the desired combination of frit and pigments.
On the other hand, the black coloration sought after in motor-vehicle applications is not obtained systematically with other types of recyclable compositions. In particular, tests carried, out by replacing all or some of the Bi2O3 with a less expensive oxide, such as zinc oxide, have not made it possible to obtain the desired black coloration, whether the Bi2O3 is replaced with a less expensive oxide in the glass frit powder before adding the manganese compounds in the first process described in the previous paragraph, or whether the raw material or materials used for obtaining Bi2O3 is or are replaced with one or more raw materials used for obtaining a less expensive oxide in the mixture of raw materials in the direct process described in the preceding paragraph.
Thus, there is a need to develop recyclable black enamel compositions which are less expensive than previous bismuth-based compositions. This need is satisfied by the present invention.
The enamel compositions provided by the invention are black enamel compositions, i.e., enamel compositions having a black color after firing, which are recyclable and comprise at least zinc.
Until now, such compositions were inconceivable due to the above mentioned coloration problems or due to recycling problems (less expensive compositions do exist but they cannot be recycled). The present invention has succeeded in developing such compositions by devising a particular process for obtaining an enamel, this process comprising the following steps of melting glass forming materials comprising at least bismuth, silicon, boron and manganese, at temperatures greater than 900xc2x0 C., and then adding a glass frit comprising at least zinc to the mixture obtained after this direct melting.
In one embodiment of the invention, the process for manufacturing a recyclable zinc-containing black enamel composition comprises the steps of melting glass forming materials comprising at least bismuth, silicon, boron and manganese together at temperatures greater than about 900xc2x0 C. to form a first mixture; and then adding a glass frit comprising at least zinc to the first mixture to obtain a second mixture that can be applied to form an enamel coating.
In the process, the melting step can be carried out above about 1050xc2x0 C. Glass frit containing no pigments, and optionally with a medium, is added to the first mixture. The zinc-based glass frit can be added in an amount sufficient to represent about 20% to about 55% by weight of the second mixture. The process may further comprise grinding the first mixture before the zinc-based glass frit is added thereto.
Enamel compositions can be obtained by the above described process. Preferably, the enamel compositions are essentially free of chromium, copper, nickel or cobalt and may further comprise a medium.
The enamel compositions may comprise a mixture of a first composition obtained by melting glass forming materials comprising at least bismuth, silicon, boron and manganese at temperatures greater than about 900xc2x0 C. and a second composition in the form of at least one glass frit comprising at least zinc. The enamel compositions may further comprise a medium.
In another embodiment of the invention, a glass substrate may be enamelled wherein at least part of a glass substrate is at least partially coated with an enamel composition as described above, and then the substrate is subjected to a heat treatment so as to bake the enamel composition thereon and form an enamel coating. The invention may also include glazings comprising at least one glass sheet coated, on at least part of at least one side, with at least one layer of an enamel having a composition as described above.
The raw materials used in the process according to the invention may be natural materials, for example, sand, colemanite, etc., or synthetic materials, for example, Bi2O3, etc. The bismuth, silicon, boron and manganese provided by the raw materials used generally are in the form of salts (nitrate, carbonate, etc.) and/or of oxides. The glass forming materials used in the process of the invention make it possible to obtain, after melting, a mixture or frit based on bismuth, silicon and boron. The elements are essentially present and are expressed hereinafter in the compositions in the form of the following oxides, respectively: Bi2O3, SiO2 and B2O3. Likewise, each other compound in these compositions will be expressed hereafter in its form commonly present, analyzed and expressed in these enamel frits or compositions. The inventive mixtures also include at least one manganese compound as pigment(s).
Preferably, the manganese compound or compounds present in the above mentioned mixture (hereafter simply called xe2x80x9cthe mixturexe2x80x9d or xe2x80x9cthe primary compositionxe2x80x9d) form the main pigments of the mixture, it being optionally possible for this mixture to include one or more other pigments, but in small amounts (amounts which remain, in particular, for each other optional pigment, less than the amount of manganese compound(s)). Advantageously, the manganese compound or compounds represent at least about 50% by weight of the pigments present, preferably at least about 75% by weight of the pigments present, and particularly preferably are the only pigments present in the mixture. In particular, and so as to obtain a composition according to the invention having good recyclability, this mixture advantageously contains no chromium oxides, copper oxides, cobalt oxides or nickel oxides and also contains no other chromium-, copper-, cobalt- or nickel-based compounds, such as copper chromates, cobalt chromates, etc. Preferably, it also contains no other coloring oxides, such as iron oxides. The amount of pigment(s) in the mixture is generally from about 20% to about 50% by weight of the mixture.
The manganese compound or compounds are generally provided in the form of manganese salt(s) and/or manganese oxide(s), for example, MnO2 and/or Mn2O3 and/or Mn3O4 and/or MnO, and are preferably provided in the form of manganese carbonate(s) and/or of MnO2.
In most cases, the raw materials used in the process according to the invention comprise, in addition to the compounds already mentioned, one or more alkalis (for example, sodium carbonate and/or sodium nitrate) and alumina. Preferably, the raw materials used are chosen so as to obtain the following mixture after melting, the proportions being expressed in percentages by weight:
The raw materials in the process according to the invention are preferably melted at temperatures greater than about 1050xc2x0 C. or even greater than about 1100xc2x0 C. the fulfilment of this condition making it possible to obtain the desired black coloration directly during the subsequent firing of the enamel, without the need for an additional heat treatment of the mixture, such as an annealing treatment. On the other hand, such an additional heat treatment of the mixture may be desirable if the direct melting is carried out at temperatures of less than about 1050xc2x0 C., i.e., to say mainly between about 900xc2x0 C. and about 1050xc2x0 C., in the process according to the invention. The annealing taking place, 30 for example, at temperatures from about 480xc2x0 C. to about 550xc2x0 C. or even as high as about 650xc2x0 C., before adding the frit comprising at least zinc, and being conducive, if necessary, in this case, to the appearance of the black coloration. The melting point of the raw materials in the process according to the invention is therefore chosen to be greater than about 900xc2x0 C., preferably greater than about 1050xc2x0 C., and as a general rule does not exceed about 1300xc2x0 C.
The mixture obtained after melting the raw materials is then generally ground into powder form, the addition of the glass frit comprising at least zinc (called hereafter zinc-based glass frit) to the mixture preferably taking place after this grinding (the zinc-based frit then also being preferably provided in powder form). In a variant, the zinc-based frit (obtained by direct melting or already in powder form) may be added to the mixture before the zinc-based frit/mixture combination is ground.
Preferably, the grinding carried out is fine grinding so that at least about 90% by weight of the particles forming the powder have a diameter of less than about 40 xcexcm, preferably less than about 20 xcexcm and particularly preferably less than about 10 xcexcm (this fine grinding making it possible to obtain better results in terms of opacity of the enamel). Where appropriate, the final powder comprising the ground mixture and the ground zinc-based frit is then put into paste form in a medium, for deposition on a surface to be coated and final firing of the enamel. In a variant, the zinc-based frit has already been put into paste form in a medium while being combined with the mixture.
In the process according to the invention, two particular separate compositions are thus combined at a very particular moment in the process. A first composition is made of the mixture and a second composition includes at least the zinc-based glass frit. This combining of particular compositions is carried out under such conditions that make it possible to obtain a particularly inexpensive composition, particularly with respect to a composition comprising only Bi2O3 as intermediate oxide, while still remaining as a recyclable composition. It also makes it possible to obtain the desired reproducible black coloration in motor-vehicle applications, such a black coloration not being obtained when the combining is carried out in a different manner. Preferably, the composition added to the mixture (this composition being called above second composition) essentially includes the zinc-based glass frit, whether in a medium or not, and especially contains no pigments, as the addition of pigments to the mixture/zinc-based frit combination possibly can be prejudicial to the formation of the black color or to the recyclability of the enamel obtained. The composition added to the mixture particularly contains no manganese compounds and, like for the mixture, contains no chromium oxides, copper oxides, cobalt oxides or nickel oxides nor any other compound based on chromium, copper, cobalt, nickel or possibly iron.
Preferably, the zinc-based glass frit is added to the mixture so as to represent about 20% to about 55% by weight of the mixture/zinc-based glass frit combination. Generally, the zinc-based glass frit comprises, apart from zinc (present as intermediate oxide and expressed in ZnO form), other oxides such as B2O3 or SiO2.
In a preferred embodiment of the present invention, the zinc-based glass frit has, for example, the following composition, expressed in percentages by weight:
The enamel composition thus obtained in the process according to the invention is a recyclable black enamel composition comprising at least zinc, as defined according to the invention. The composition according to the invention may also be defined as an enamel composition containing no chromium, copper, nickel, cobalt or possibly iron compounds; this composition comprising zinc and being able to give a black coloration (L*xe2x89xa65; |a*|xe2x89xa62 and |b*|xe2x89xa62) after firing. The composition according to the invention may particularly and advantageously be obtained by the process according to the invention.
The enamel composition according to the invention generally comprises a mixture of oxides (frit), including at least ZnO. The expression xe2x80x9cenamel compositionxe2x80x9d should be understood according to the invention to mean the composition of the enamel in question before it is fired, the enamel after firing essentially being in the form of a colored glassy matrix.
In general, the enamel composition according to the invention also includes other oxides, particularly Bi2O3 and MnO2, as well as silicon oxide SiO2 acting as a network-forming oxide, aluminum oxide and boron oxide, and possibly other oxides such as sodium, lithium, potassium, calcium, magnesium or titanium oxides, or the like. Preferably, the composition according to the invention, obtained particularly according to the process of the invention, has the following composition, expressed in percentages by weight:
Preferably, for reasons associated in particular with recycling, the composition includes less than 1%, advantageously less than about 0.1% and preferably less than about 0.05% by weight of lead oxides. It is most preferred that no lead oxides are present. Also, the composition preferably contains no other problematic elements, such as cadmium oxides, chromium, copper, nickel, cobalt or iron elements as mentioned above.
In an advantageous embodiment of the invention, the enamel composition furthermore comprises less than about 10% by weight and preferably less than about 5% by weight of silver particles and, more generally, comprises less than about 10% of any silver-based compound or any conductive particles.
As already mentioned above, the enamel composition according to the invention may comprise a medium which allows the composition to have the desired viscosity for application to the substrate and allows it to bond to the substrate. This medium may be any medium normally used in conventional enamel compositions and may especially include solvents, diluents, oils such as pine oils and other vegetable oils, resins such as acrylic resins, petroleum fractions, film-forming materials such as cellulosic materials, etc. The proportion of medium in the composition ready to be deposited is preferably from about 15% to about 40% by weight of the composition.
The enamel composition according to the invention also advantageously has a firing temperature (or melting point) of less than about 700xc2x0 C., for example, from about 550xc2x0 C. to about 650xc2x0 C. In the process according to the invention, the raw materials and the zinc-based frit used are, in particular, chosen so as to preferably obtain a composition having this firing temperature. The expression xe2x80x9cfiring temperature of the enamel compositionxe2x80x9d should be understood according to the invention to mean the firing temperature of the enamel in its form as deposited on the substrate to be coated. It corresponds, in the field of enamels, to the minimum temperature at which xe2x80x9csufficientxe2x80x9d sintering of the composition is observed, this xe2x80x9csufficientxe2x80x9d sintering being especially manifested by the disappearance of the capillary effect of the enamel during sintering. A person skilled in the art knows how to measure this melting point, for example by passing an inked pen (e.g. more specifically a felt) over the enamel after the latter has been raised to a treatment temperature and then cooled and then by noting the lowest treatment temperature for which the trace, left across the cooled enamel by the solvents of the ink when they are absorbed by the enamel by capillary effect, disappears. In the production of an enamelled substrate, the temperature chosen for firing the enamel deposited on the substrate is then preferably chosen to be greater than or equal to this firing temperature.
In the process for enamelling glass substrates, especially glazings, using the composition according to the invention, the enamel composition is fired after it has been deposited on a substrate. The firing, where appropriate, takes place during the heat treatment associated with the bending and/or toughening of the substrates. Generally, the firing temperatures range from about 550xc2x0 C. to about 700-750xc2x0 C. and the firing time preferably does not exceed a few minutes. Preferably, any heat treatment carried out on the enamel composition according to the invention or on the mixture/zinc-based frit combination obtained in the process according to the invention does not exceed about 700xc2x0 C. in temperature and does not exceed a few minutes or tens of minutes. At most, a time of one hour may be used. More substantial heat treatments can possibly cause degradation of the black coloration. The fulfilment of these conditions is not prejudicial to the processing of the enamel according to the invention, however, it being possible for this enamel to be advantageously processed using the devices and under the temperature and pressure conditions normally employed for processing conventional enamels, especially those used in motor-vehicle applications.
The enamel composition may be deposited on a substrate by screen printing, by sputtering, by curtain or roll coating, or by other conventional processes. The deposition is generally followed by drying, for example using infrared light, in order to temporarily fix the enamel by removal of the diluents of the medium used for applying the enamel to the substrate. If several layers are deposited on the substrate, each layer is preferably dried before the next layer is deposited, the firing taking place on the multilayer assembly.
The optional bending and toughening of the glass substrates are carried out using known methods. The bending may especially be carried out by gravity, especially the bending of glass substrates in pairs for the purpose of producing laminated glass sheets, or by means of dies and, when the substrates are bent and toughened, the toughening may be carried out after bending the enamelled substrates, optionally within the same device.
If glass substrates have to be bent simultaneously, for the purpose of producing laminated glazings, the enamel is deposited on at least one of the substrates and the substrates are joined together and then bent. The glass substrates are then separated in order to insert at least one interlayer film of different material. The laminated glazing may be obtained by joining the assembly together by hot pressing.
The enamel obtained after firing exhibits good opacity, with an optical density of the enamel generally being greater than 2.5. The optical density (OD) is measured with a densitometer, for example the GRETAG(copyright) D200 apparatus in which a 550 nm filter is used and is related to the light transmission factor TL by the equation:
OD=log 1/TL
Moreover, regardless the initial color of the enamel composition according to the invention before firing, a black enamel of the type required for motor-vehicle applications is obtained after firing. Preferably, the enamel composition according to the invention is chosen so as to give, after firing, a black enamel having the following colorimetric coordinates, in absolute values:
L*xe2x89xa65; |a*|xe2x89xa61 (and, preferably, |a*|xe2x89xa60.6) and
|b*|xe2x89xa62 (and, preferably, |b*|xe2x89xa61).
The colorimetric coordinates L*, a* and b* were defined and proposed in 1931 by the CIE (Commission Internationale de 1""Eclairage [International Illumination Commission]) and have formed the subject of an official CIE recommendation in 1976 (International Illumination Commission, Colorimetryxe2x80x94Official Recommendationsxe2x80x94CIE Publication No. 15-2, Vienna, 1986). The above mentioned calorimetric coordinates are measured in reflection, using a Minolta CM 2002 spectrocolorimeter, under illuminant D65 at an angle of observation of 10xc2x0 and in specular excluded mode, for the enamel when on an untinted glass substrate having a light transmission factor of about 90% and a thickness of 4 mm.
The substrates coated with the enamel according to the invention also exhibit, especially because of the use of the manganese compound or compounds as all or some of the pigments, better recyclability. Thus, when the substrates coated with the enamel having the composition according to the invention are reintroduced, in cullet form, into a furnace for melting raw materials for the production of glass sheets (at temperatures generally of about 1350xc2x0 C. to about 1500xc2x0 C.), the coloration of the enamel generally disappears and does not interfere with the coloration of the glass resulting from the raw materials used. The recyclability of the composition according to the invention is particularly good when the composition contains about 1% or less of problematic components such as lead, chromium, copper, cobalt, nickel, iron, cadmium, silver or other conductive particles.
The enamel composition according to the invention can be used to coat various substrates. The substrate on which the enamel composition is deposited may be a bare glass substrate or a glass substrate already coated with one or more layers of enamel, preferably with one or more layers of enamel according to the invention. This substrate may consist of one or more glass sheets and may be toughened so as to have improved mechanical strength and heat resistance properties. The substrate coated with enamel according to the invention thus comprises at least one glass sheet coated on at least part of one of its sides with at least one layer of an enamel having a composition according to the invention. The enamel according to the invention may also be used to coat other types of substrate.
The glass substrates, especially glazing, coated with enamel according to the invention exhibit improved recyclability, these substrates generally being recyclable, especially in the form of cullet, in furnaces for manufacturing glass sheets, particularly in the most widely used furnaces for the manufacture of glass sheets by the float process, with amounts possibly ranging up to at least about 15%, or even at least about 50%, by weight of the charge of the furnaces with the enamel generally constituting from about 0.1% to about 0.5% by weight of the glass cullet. The substrates coated with enamel according to the invention furthermore have mechanical properties sufficient for them to be used in motor-vehicle applications.

Process for manufacturing a recyclable zinc-containing black enamel composition