>>482
In this way, an intrinsic twist with optional pitch between that of the chiral component and infinity can be created.
The only limitation arises from the following fact. That is, for too small pitch, the structure may change to one which is periodic in a direction parallel to the cell walls.
This ‘stripe structure’ was discovered earlier by Chigrinov. This effect limits the twist to 〜 240° , the bi-stable situation can’t be used. The twist angles in commercial displays are in the range 180 〜 240° .
>>483
By the way, the order parameter of liquid crystal has a RP＾2 ( real projective plane ) -like structure, we must ‘4-dimensionally’ paste a punctured ball with a Mobius-band to realize such a projective plane.
It’s told that people in Jyoumon-period (縄文時代) have an ability to 4-dimensionally perceive various objects, in the sense, their abilities is suitable for dealing with such an order parameter.
>>483
Another major difference of super-twisted displays is that the polarizers on both sides are placed in a non-standard way.
They are not parallel to the respective liquid crystal molecule orientations as in the twisted nematic cell. This becomes necessary because of the residual twist in the select state which makes the standard way of operation impossible.
一
>>486
Instead the ‘interference mode’ is used where one has to accept a highly coloured off-state.
According to some experiments, they show periodic zeros for the different colours as before but not the general decaying envelope.
Therefore, the transmission for ‘wrong’ colours is much higher than in the waveguide mode.
The resulting colour is chosen in a way that the subjective contrast is still acceptable ー usually yellow or blue.
Therefore, in the context of super-twisted nematic displays one speaks about normally-yellow and normally-blue displays.
>>487
Several principles are used to improve this situation.
In using coloured backlight, one can achieve colours of the transmitted light.
Replacing the polarizers by dichroitic devices, one can let the opposite colour of the off-state through so that additive mixing results approximately in white.
Extremely thin cells don’t show this coloration but have a low transmission even in the ‘white’ state.
>>488
The best but also most expensive solution is the optical compensation. This principle is most easily explained from the double super-twisted nematic cell which was used as a standard laptop display application for a long time.
There, one combines two layers of STN liquid crystal with opposite twist.
一
>>489
This is done by mirroring the direction of the orienting coatings on the cell walls and using the enantiometric chiral component in the liquid crystal mixture.
Without any calculation symmetry tells that a light beam crossing both structures will remain unchanged in its polarization.
一
>>490
All effects bi-refringence of the first layer are identically compensated by the second.
This means one can get a white off-state by parallel polarizers and a black one by perpendicular polarizers.
The ‘active’ layer, a voltage is applied to get the device into the on-state only on one of the liquid crystals. In this way, the symmetry is destroyed and the cell switches to the opposite colour.
>>491
As the construction of the second mirrored liquid crystal layer is very expensive, the compensation of developed devices has been accomplished with a solid foil ( about 2003 ). Such a foil is made from a polymer containing liquid crystalline side-groups.
Here, the demerit with respect to the DSTN ( double super-twisted nematic ) principle is that the optical compensation (≒ optical correction) will reach the complete condition only for one wavelength and one temperature.
Therefore, a slight coloration of the off-state is resulted from rise in ‘abnormal’ ambient temperatures.
>>492
5.2 Active Matrix Displays
The current standard for PC display mainly adopts AM ( active matrix ) or TFT ( thin film transistor ).
Instead of solving a problem of highly multiplexed addressing by chemical methods, we used an electronic one for that.
Each display pixel is equipped with its own driver. This is only possible by putting the driving transistor close to the pixel into the display’s matrix.
>>493
One of the glass substrates contains a matrix of thin film transistors whose gates are connected to the row lines and source electrodes are connected to the column lines.
The pixels are not directly constructed as the intersection of row and column lines.
They are rather created by individual electrode patches connected to the drains of the TFTs. The counter-electrode extends over the whole area of the opposed glass substrate.
一
>>494
This integration of a transistor onto the glass matrix was based on a way devised by Lilienfeld in 1933 ( amazing ! ).
In principle, it’s a field-effect transistor similar to the well-known MOS ( Metal-Oxide-Silicon ) FET.
But, instead of the conventional way to make the transistor from bulk material, here it’s made by coating a glass cell wall with semiconductor, conductor layers and etching.
>>495
The source and drain electrodes are connected by a layer of n-type amorphous hydrogen-doped silicon.
The metal gate electrode is placed below the semiconductor layer insulated by silicon nitride.
Because the carriers in the semiconductor correspond to electrons rather than holes, a positive voltage on the gate enhances source-drain conductivity and a negative voltage suppresses the conductivity.
So, the TFT can be viewed as an electronically controllable switch.
一
>>496
The TFTs simply act as switches. The thin-film transistors of rows are sequentially opened by applying row-by-row a positive voltage.
When the source-drain line is opened, the voltage on the column lines is forwarded to the liquid crystal cell.
After a row is addressed, the TFT will close again and shield the pixel from the voltage applied to the next row.
The electric field on the liquid crystal is kept by own capacity, and it (＝ the electric field) is kept by an additional capacitor in most cases.
>>497
TFT active matrix displays are currently ( about 2003 ) the best solution for high resolution displays.
Cross-talk can be avoided except for capacitive effects. There is no limits in the selective / non-selective voltages.
Therefore, normal TN liquid crystals can be used, and analog grey scale addressing is possible.
一
>>498
Meanwhile, TFT displays are three times more expensive than DSTN displays. Therefore, though applications of this technology have been widely circulated over PC & video displays, they are already high in cost.
The market fraction of TFT displays was 74 % in 1999 . It’s expected to further be increased.
Because they are more expensive than DSTN devices, they will sooner or later disappear from the market of high-resolution displays ( in 2003 ).
>>499
During the year since its discovery TFT technology has made an enormous progress. The image resolution is already approaching that of printers a decade ago.
※ one of the TFT displays was manufactured by IBM .
It boasts a so-called QUXGA resolution of 3,840 × 2,400 pixels. This type at a diagonal size of 22.2′′ ( 564 mm ) corresponds to a pixel distance of 0. 1245 mm or a pixel density of 204 per inch. The retail price of the monitor based on this display is well above 15,000 US$ ( in 2003 ).
>>499
More precisely, it’s expected that though TFT displays are more expansive than DSTN displays, the former technology is more popular than the latter one because of good performance, accordingly devices at the expense of DSTN will disappear from the market in display at that time.
>>500
§ 6 Backlihhting
As indicated previously, some LCD display principles require backlihhting. In other cases, the applications forces to adopt backlight in addition to the ambient light.
Therefore, design of the light source is often important for the construction of a LCD display module.
Because about 90% of the electrical power is consumed by a backlight for now.
Accordingly, its power consumption is the major factor determining an operation time of battery powered device.
>>502
By the way, a cold cathode fluorescent lamp is the best available source with respect to power consumption. Namely, the low power consumption enables use of the light source for notebook PCs without exception.
The filament lamp and electro-luminiscent foil are used in small scale applications as wristwatches and cellular phone displays.
Because the display lighting is only inter-mittently activated, the lifespan isn’t a subject to be solved so much, rather the cost for production is more important.
If a coloured backlighting is requested, light emitting diodes have a limited application.
>>503
Because of its widespread application, a cold cathode fluorescent lamp ( CCFL ) must be taken into consideration in detail.
CCFLs are commonly called ‘neon’ lamps. They had been utilized since 1910, that is, those ‘neon’ lamps were first adopted in advertising signs.
Because a high voltage required for use of CCFLs was mostly restricted to this ‘neon sign’ application until the appearance of LCD backlighting.
>>504
A CCFL consists of a tube filled with a mixture of mercury vapour and ‘penning gas’ at about 7 hPa pressure.
The gas discharge mainly produces a 253.7 nm ultraviolet radiation from mercury atoms. Meanwhile, the penning gas enhances the ionization of mercury at lower voltage.
The interior of the tube is covered with a mixture of phosphorus to convert ultraviolet into visible light.
A broad range of colours can be obtained by an appropriate choice of phosphorus.
>>505
Furthermore, high voltage is required for the major drawback of CCFLs. Because electrical emission is only based on electrical voltage,
And, CCFLs have no heating of the cathode to facilitate emission.
※ Then, the voltage amounts is 25 〜 50 V/ cm.
This means that CCFLs need a power supply of 800 〜 1000 V for notebook PC applications.
So that, so-called ‘inverters’ is needed, this circuit can convert the DC power from a battery into a sinusoidal AC voltage.
※ The voltage is transformed up to the optionally desired voltage.
>>506
§ 7 Reflective Liquid Crystal Displays
Reflective liquid crystal displays offer some competitive merits over the transmissive ones in low power consumption, sunlight readability and film-like image quality. The readout light comes from ambient.
As backlight isn’t used in this case, both its power consumption and panel weight are reduced.
>>507
In a bright outdoor environment, the images of a transmissive display could be washed out by sunlight. Since reflective displays utilize ambient light as reading source. The brighter the ambient light is, the more vivid the displayed image gets.
In most reflective LCDs, the thin-film-transistor ( TFT ) are imbedded under-neath a reflector.
Therefore, the aperture ratio is as large as 90 %, it can still be obtained even for a high-resolution device ( 1024 × 768 ).
High aperture ratio makes the displayed images like film quality.
※ But, the screen door effect in some types of transmissive LCDs no longer exists.
>>508
Besides, several reflective display technologies for LCD have been developed such as digital micro-mirror device, grating light valve, inter-ferometric modulation, electrophoretic display and rotating ball display.
Each technology has both merits and demerits. Some devices are more suitable for direct-view and others are preferred for projection displays.
一
>>509
Within the liquid crystal family, several light modulation mechanisms have been discovered. Theee include phase retardation, polarization rotation, absorption, light scattering and Bragg reflection.
Phase retardation and polarization effects need to incorporate at least one polarizer.
一
>>510
A reflective direct-view display adopting a polarizer can achieve 30 - 40 : 1 contrast ratio and good color saturation, except that the light throughput is sacrificed.
Meanwhile, the display mechanisms including absorption, light scattering and Bragg reflection don’t require any polarizer.
High brightness and wide view angle are necessary requirements for such displays. But their contrast ratio is usually limiited to 5 - 10 : 1 .
>>511
Several types of reflective direct-view liquid crystal displays have been developed.
They can be roughly categorized by the number of adopted polarizers. The benchmark for these types of reflective displays is at white paper.
A white paper and newspaper respectively has reflectivity of 80 and 55 % and contrast ratio of 12 : 1 and 6 : 1 .
All electronic displays developed until now still can’t match the performance of a white paper in reflectivity and viewing angle.
>>512
§ 7.1 Two-polarizer R-LCDs
Wristwatch displays use two polarizers. A LC cell is sandwiched between two crossed linear polarizers. The 90° twisted nematic ( TN ) cell is used as light switch.
Behind the second polarizer, a diffusive reflector reflects the incident light back to the viewer.
The 90° TN cell has been widely used for transmissive display due to its high efficiency, weak color dispersion, high contrast ratio and low operation voltage.
>>513
But, when a 90° TN cell cell is used for reflective display, two crossed polarizers are required to achieve high contrast ratio.
The second polarizer put between the back substrate and diffuse reflector not only reduces brightness but also causes parallax ( double image ) to bring limits on resolution.
Thus, the two-polarizer R-LCD isn’t suitable for high resolution displays.
>>514
As yesterday was 08/12 , I abruptly turn a topic into an other content.
「The plasticity of brain」was planned as one of the prior researches in the second half of the 1980’s by the ministry of education ( the ministry of education & science at present ) in Japan.
Unfortunately, Nobuaki.Tsukahara who would get the chief of the research died in a plane accident on 1985/08/12 .
>>515
・ Memorization, learning and neuro-computing
Neurons mainly bear learning, memorization, those processes are based on variations of synapse ( plasticity of synapse ).
If a learning newly holds, the number of synapses, the quantity of secreted neurotransmitters increase. So that, the electric potential of synapse rises and the nerve cell gets easy to be excited.
>>516
In case of forgetting, the change of synapse turns to be reverse of the above case.
Brain has remarkable flexibility, its neural circuits are modified and reformed by various internal and external factors.
And, functions of neural circuit often continue to vary.
一
>>517
The visual system is a typical example to show the plasticity of brain.
If a kitten is put in a visual environment of only vertical stripes for 3 〜 14 weeks after the birth,
it will get difficult for the cat to see horizontal contours.
And, most of visual fields become put in the range of ±30° in the vertical direction.
※ Then, simple type cells selectively react to segmental stimuli in some azimuth ( direction ).
>>518
Namely, in this case, neurons of the visual field to react to horizontal segments almost disappear.
※ Such a change doesn’t happen over three months after the birth.
The neural circuit of brain isn’t completed just after the birth, it will be remarkably modified according to given stimuli.
※ For example, Lorenz made clear special learnings found out in the beginning after the birth called ‘imprinting’ from the viewpoint of ethology.
>>519
・ The plasticity of brain in the mature step
It has been regarded that a formed nerve net once can never be varied again after the formation.
But, it has been made clear that a completed neural circuit of brain once also can be changed in its functionality, shape according to environmental variations.
→ the plasticity of brain in the mature step
>>520
As an example, a clinical case of ‘replacement of nerves’ to a patient whose nerve from the spinal cord to the brachial muscle is cut off because of an accidental injury of spinal cord is known.
Then, a part of intercostal nerves ( governed by a respiratory muscle ) was transplanted into the musculo-cutaneous nerve of the brachial muscle.
First, the arm moved together with the respiration, soon the person could voluntarily move the arm namely bend the elbow independently of respiration.
>>521
・ Foundations of plasticity of synapse
Plasticity of synapse is roughly divided into two types as follows.
① Plasticity on the conjunction among synapses
② Plasticity of transmission on a synapse
In a case to manage increased works in an office, following two ways are presented.
( a ) Increasing a number of members in the office (≒ a number of synapses )
( b ) Improving the ability for managing of each member (≒ raising the transmitting efficiency over each synapse )
Then, ( a ) , ( b ) correspond to ①, ② respectively.
>>522
As an example of ① , a phenomenon called ‘germination’ is found out over nerve, muscular system, red nucleus and hippocampus, etc.
Synapses are newly formed from healthy ( sound ) nerve fibers in this phenomenon.
There are two types of ② namely increasing & decreasing in transmitting efficiency,
The former is found out in a hippocampus, a sea-hare ( one of the mollusks ). Meanwhile, the latter is found out over a cerebellum.
>>523
◎ Examples of synaptic plasticity
・ The plasticity of conjunction among synapses (≒ the plasticity of coupling synapses)
A cross-sewing operation was performed on a foreleg of a cat to replace the nerve for bending muscle of peripheral nerves with the nerve for stretching muscle.
After 2 〜 8 months since the operation, first the foreleg of the cat moves oppositely to the intention ( namely, when the cat tries to bend the arm, it’s stretched. Inversely, when the cat tries to stretch the arm, it’s bent ), soon the cat gets to be able to perform usual behavior such as catching a bait in the way before the operation.
A synapse is formed of fibers from the motor area of a cerebrum at a red nucleus.
→ the cerebral red nuclear synapse
>>524
Synaptic potentials from red nuclear cells governing both front & rear legs were measured.
As the result, it was found out that cerebral red nuclear synapses were newly formed on red nuclear cells governing the foreleg in the above case.
※ N.Tsukahara and others made clear the plasticity of brain in the cellular level to variations on peripheral function.
>>525
・ The plasticity of transmission on synapses
If a temporal lobe including the hippocampus in a deep part of a cerebrum is damaged,
the patient will fall in a serious defect of memory.
Namely, a hippocampus plays important role for formation, maintenance and control of memory.
A typical example of improved transmission on synapses has been found out on a hippocampus.
T.Bliss and others reported that if impulses successively pass through a synapse between perforated path and granule cell, the improvement in transmission efficiency is maintained for about several hours.
※ Such a phenomenon is called ‘long-term potentiation’ .
>>526
If a subject is put in an environment which is seeable oppositely in right & left, the adaptive mechanism of the vestibular oculomotor reflection works and the cerebellum plays important role.
In such a case, in the cerebellar cortex, an input-system is formed of climbing fibers and mossy fibers, neuraxons from Purkinje cells behave as output-systems.
Furthermore, an excitatory synaptic junction of a Purkinje cell with a climbing fiber can be found out in this case.
一
>>527
Then, signals from a mossy fiber are relayed to parallel fibers through granule cells, parallel fibers as the output system form an excitatory synaptic junction with a Purkinje cell.
一
>>528
And, informations from about 6000 separate mossy fibers converge on a Purkinje cell.
But, if a Purkinje cell almost-simultaneously and successively receives signals from both parallel fibers and climbing fibers, the transmission efficiency on synapses between the Purkinje cell and parallel fibers falls.
一
>>529
By the way, J.S.Albus and D.Marr presented it as a hypothesis about 1970 that information-processing on a cerebellum may be same as the principle of percep-tron.
Ito and others have investigated variations over synaptic junctions with a Purkinje cell to physiologically check the hypothesis.
〈 A reference 〉
「The cerebellum as a neuronal machine」
J.C.Eccles, M.Ito and J.Szentagothai, ed.
( Springer, 1967 )
>>531
PDLC and LC gels are used to prepare light scattering devices. Ch-LCD utilizes Bragg reflection. And, GH display takes merits of the anisotropic absorption of dichroic dyes.
Ch-LCD and GH displays of them are better than PDLC and LC gels in momentum.
一
>>532
A main advantage of the Ch-LCD is that the reflected light is already colored.
Therefore, it’s possible to realize a color display without using color filters.
Because it’s unnecessary for polarizer in the case, the reflectivity of a Ch-LCD is at least 6 times higher than a reflective display adopting a polarizer and color filters.
>>533
The viewing cone of a Ch-LCD without polarizers is wider than 60° except that its contrast ratio is in the 5 - 10 : 1 range.
2 or 3 RGB panels are stacked together as one approach to achieve multiple colors.
Accordingly, ‘parallax’ can be regarded as a potential problem of the stacking method. For example, an incident light & a reflected light pass through different pixels.
>>535
Mixed color is induced by ‘parallax’ . This subject is serious for preparing a high-resolution LCD .
The operation voltage of a Ch-LCD is inversely proportional to the pitch length. The operation voltage of a Ch-LCD is in the vicinity of 20 V rms due to the short pitch involved for visible displays.
Besides, as Ch-LCD is bi-stable, its low power consumption is particularly suitable for electronic books.
>>536
The guest-host ( GH ) display can be driven by TFT arrays. But, its contrast ratio is limited to 〜 5 : 1.
Because the operation principle of a GH display is based on utilization of absorption anisotropy of dichroic dye molecules doped in an aligned LC host.
Normally, a GH display system consists of 1 〜 5 % of absorbing dye molecules dissolved in a LC host.
The host LC is highly transparent in a visible spectral region and the guest dyes strongly absorb one polarization of an incoming light and transmit other polarization.
>>537
Special device configurations have been developed to avoid use of any polarizer in a GH display.
For example, the Coke-Kashow cell uses a homogenous GH cell with a quarter-wave film put between the rear substrate and the reflector.
The White-Taylor cell uses chiral dopant to form twisted GH layers. So that, both polarization of an incident light can be absorbed while traversing through the GH LC layer twice.
一
>>538
The double cell uses two orthogonal homogenous cells, the first GH layer is responsible for one polarization and the second layer for the other polarization.
All the three cells in the above have their own pros and cons. The typical performance of a GH LCD is 50 〜 60 % reflectivity, 5:1 contrast ratio, 〜 ± 60° viewing angle and 50 〜 80 ms response time.
Low power consumption is an main attractive character of a GH display.
>>539
§ Single-polarizer R-LCD
For a reflective LCD with one polarizer, the light still traverses the polarizer twice, so that the maximum light throughput is limited to 〜40 %.
But, as compared with two-polarizer LCD, two merits are brought by a single-polarizer LCD.
>>540
Fiirst, parallax is eliminated by removing the second polarizer put between a back glass substrate and a reflector, next, the reflectiivity is raised by 25 % with removing the second polarizer.
Meanwhile, though its reflectivity is lower, the single-polarizer LCD exhibits a higher contrast ratio than a non-polarizer LCD.
In this case, contrast ratio is necessary for color displays.
一
>>541
If the contrast ratio is 5 〜 10 : 1 , light is leaked out of a color pixel and relatively larger mixed colors are brought.
If contrast ratio exceeds 30 : 1 , light leakage in a color pixel is remarkably improved however that state is still far from the perfect condition.
>>542
In case of reflective display, it’s not easy to get contrast ratio higher than 50 : 1 under ambient light condition due to surfacial reflections.
A compromise between display brightness and contrast ratio is brought by the single-polarizer LCD and it has become the mainstream in approach ( about 2003 ).
>>543
Several cell configurations have been devoloped for single-polarizer reflective LCDs.
For example, the mixed-mode TN cell, super-twist TN cell, homotropic cell, film-compensated homogeneous cell and π-cell all have their own merits.
544
For passive matrix display, STN with 220° 〜 240° twist angle has been considered for achieving high duty ratio.
Meanwhile, for active matrix display, a large cell gap tolerance to accomodate the bumpy reflector surfaces is brought by MTN cells, so that, a good contrast ratio can still be obtained.
Furthermore, for reflection type projection display, MTN and homotropic cells are favored choices due to their high contrast ratio.
>>545
The viewing angle of a reflective cell is equivalent to a two-domain transmissive cell. Because the mirror image effect is realized by the incident and reflected beams. For computer monitor, such ± 45° viewing angle is in-sufficient.
But, for handheld displays, the panel can be conventionally adjusted to fit the viewer’s position. Therefore, viewing angle isn’t a critical issue for most handheld reflective LCDs.
>>546
For reflective direct-view displays, design and fabrication for a reflector is probably the most critical concern. An ideal reflector reaches two criteria : 1 .
If the requirement is satisfied, displayed images will be run to viewers without overlapping with surfacial reflection.
一
>>548
If images are mixed with glares, the contrast ratio will be considerably reduced.
Accordingly, we must prepare sufficiently wide viewing cone and optical gain for avoiding that. A specular mirror has too narrow viewing angle and can’t be used alone for reflective display.
A Lambertian reflector has uniform scanning all over the angles by contrast, so that the light intensity in the preferred viewing cone is reduced.
>>549
Extensive efforts have been put into design & fabrication for reflector with acceptable viewing angle while providing optical gain preserving good contrast ratio.
So far, four types of reflectors have been investigated :
( 1 ) light control films,
( 2 ) rough surfacial reflectors,
( 3 ) holographic reflectors,
( 4 ) cholesteric reflectors
一
>>550
A light control film is designed so as to guide images to the observer at approximately normal viewing direction, the viewing direction is well separated from the specular angle.
This film has been applied to STN, PDLC and cholesteric displays. The display brightness and contrast ratio are remarkably improved.
一
>>551
Meanwhile, the bumpy reflector gets higher and it diffuses the incident light to a preferred viewing cone to avoid overlapping with the specular reflection.
In fact, a structural change is incorporated into it.
The holographic reflector can be either laminated to the backside of the display or integrated with color filters.
一
>>551
Meanwhile, the bumpy reflector gets higher and it diffuses the incident light to a preferred viewing cone to avoid overlapping with the specular reflection.
In fact, a structural change is incorporated into it.
The holographic reflector can be either laminated to the backside of the display or integrated with color filters.
一
>>552>>553
Though the former approach is simple, its usefulness is limited to low resolution because undesirable parallax is caused by the simpleness.
Surely, designs for internal holographic reflector is under improvement, but they hold promise for displays with high brightness, high contrast and excellent chromaticity.
Finally, cholesteric liquid crystal layer has also been utilized as diffusive reflector for some bi-refringence color reflective LCDs.
一
>>554
§ ‘Transflective’ Displays
A reflective LCD relies on ambient light to read out displayed informations. When the ambient light is dim, the display isn’t readable whether built-in light is available or not.
We must develop a trans-flective display to overcome such a problem.
In a trans-flective LCD, each pixel is split into reflective sub-pixels ( R ) and transmissive sub-pixels ( T ). Usually, the R & T area ratio is 4 : 1 in favor of reflection.
The backlight is used for dark ambient only for conserving power.
>>555
In the single cell gap approach, the cell gap for R modes is equal to that for T modes and it’s optimized for R-mode.
As a result, the light transmittance for T-mode gets lower than 50% because the light only passes the LC layer once.
Meanwhile, in the double cell gap approach, the cell gap for T-pixels is twice that for R-pixels.
Besids, both R and T have high light efficiency. But, the response of T mode is four times slower than that of R mode.
>>556
A common problem for most transflective displays is that both R & T pixels have different color saturation.
For R pixels, the ambient light passes a color filter twice, on the other hand, for T pixels, the backlight only passes the color filter once.
The pigment concentration or the color filter thickness of the transmissive pixels should be twice that of the reflective ones to realize equal color saturation. For simplicity, this problem is ignored in most trans-flective displays.
一
>>557
According to existing technologies ( in 2003 ), it’s possible to realize 40-inch direct-view LCDs. But, high cost is needed for producing them. To overcome such a problem, projection is prepared so as to be alternative way for achieving large-sized display ( for example, high definition TV, boardroom presentation and electronic cinema ).
Two types of projection displays have been often proposed : front & rear projections. In case of front projection configuration, a distant screen is utilized to view a magnified image. Meanwhile, in case of rear projection configuration, the magnification optics is enclosed in back of an imaging screen to produce a self-contained system.
Both transmissive and reflective LCDs have been considered for projection displays ( about 2003 ).
>>557
According to existing technologies ( in 2003 ), it’s possible to realize 40-inch direct-view LCDs. But, high cost is needed for producing them. To overcome such a problem, projection is prepared so as to be alternative way for achieving large-sized display ( for example, high definition TV, boardroom presentation and electronic cinema ).
Two types of projection displays have been often proposed : front & rear projections. In case of front projection configuration, a distant screen is utilized to view a magnified image. Meanwhile, in case of rear projection configuration, the magnification optics is enclosed in back of an imaging screen to produce a self-contained system.
Both transmissive and reflective LCDs have been considered for projection displays ( about 2003 ).
>>557
According to existing technologies ( in 2003 ), it’s possible to realize 40-inch direct-view LCDs. But, high cost is needed for producing them. To overcome such a problem, projection is prepared so as to be alternative way for achieving large-sized display ( for example, high definition TV, boardroom presentation and electronic cinema ).
Two types of projection displays have been often proposed : front & rear projections. In case of front projection configuration, a distant screen is utilized to view a magnified image. Meanwhile, in case of rear projection configuration, the magnification optics is enclosed in back of an imaging screen to produce a self-contained system.
Both transmissive and reflective LCDs have been considered for projection displays ( about 2003 ).
>>557
According to existing technologies ( in 2003 ), it’s possible to realize 40-inch direct-view LCDs. But, high cost is needed for producing them. To overcome such a problem, projection is prepared so as to be alternative way for achieving large-sized display ( for example, high definition TV, boardroom presentation and electronic cinema ).
Two types of projection displays have been often proposed : front & rear projections. In case of front projection configuration, a distant screen is utilized to view a magnified image. Meanwhile, in case of rear projection configuration, the magnification optics is enclosed in back of an imaging screen to produce a self-contained system.
Both transmissive and reflective LCDs have been considered for projection displays ( about 2003 ).
>>558 〜
§ Transmissive Displays
We briefly show a LCD projector using three transmissive poly-silicon thin-film-transistor ( TFT ) panels.
The incoming white light from a lamp is divided into three channels by dichroic mirrors. In each channel, a LCD panel is sandwiched between two linear polarizers.
The 90°-TN and Vertical Aligned ( VA ) cells are popular in choice, because TN cell has weak wavelength dependency, meanwhile VA cell has an un-precedented contrast ratio ( ＞ 1000 : 1 ).
In case of the X-cube, RGB beams are re-combined, the reflective lens is projected into the images on a screen.
>>558 〜
§ Transmissive Displays
We briefly show a LCD projector using three transmissive poly-silicon thin-film-transistor ( TFT ) panels.
The incoming white light from a lamp is divided into three channels by dichroic mirrors. In each channel, a LCD panel is sandwiched between two linear polarizers.
The 90°-TN and Vertical Aligned ( VA ) cells are popular in choice, because TN cell has weak wavelength dependency, meanwhile VA cell has an un-precedented contrast ratio ( ＞ 1000 : 1 ).
In case of the X-cube, RGB beams are re-combined, the reflective lens is projected into the images on a screen.
>>563 〜
Linearly polarized light is required for most LC devices. A few polarization conversion devices have been invented to convert unpolarized light into linear one.
So that, the conversion efficiency reaches 70 〜 80 % . Furthermore, an array of microlenses is utilized to raise aperture ratio of a high resolution TFT-LCD panel.
The effective aperture ratio was improved to 〜 80 % for a XGA device.
In many cases, the power efficiency of 10 〜 15 lm / watt in a projection system with three transmissive LCD panels has been routinely obtained.
Under such circumstance, 1000 〜 1500 lumens can be produced on a screen with a 100 W short-arc lamp.
>>563 〜
Linearly polarized light is required for most LC devices. A few polarization conversion devices have been invented to convert unpolarized light into linear one.
So that, the conversion efficiency reaches 70 〜 80 % . Furthermore, an array of microlenses is utilized to raise aperture ratio of a high resolution TFT-LCD panel.
The effective aperture ratio was improved to 〜 80 % for a XGA device.
In many cases, the power efficiency of 10 〜 15 lm / watt in a projection system with three transmissive LCD panels has been routinely obtained.
Under such circumstance, 1000 〜 1500 lumens can be produced on a screen with a 100 W short-arc lamp.
>>563 〜
Linearly polarized light is required for most LC devices. A few polarization conversion devices have been invented to convert unpolarized light into linear one.
So that, the conversion efficiency reaches 70 〜 80 % . Furthermore, an array of microlenses is utilized to raise aperture ratio of a high resolution TFT-LCD panel.
The effective aperture ratio was improved to 〜 80 % for a XGA device.
In many cases, the power efficiency of 10 〜 15 lm / watt in a projection system with three transmissive LCD panels has been routinely obtained.
Under such circumstance, 1000 〜 1500 lumens can be produced on a screen with a 100 W short-arc lamp.
>>563 〜
Linearly polarized light is required for most LC devices. A few polarization conversion devices have been invented to convert unpolarized light into linear one.
So that, the conversion efficiency reaches 70 〜 80 % . Furthermore, an array of microlenses is utilized to raise aperture ratio of a high resolution TFT-LCD panel.
The effective aperture ratio was improved to 〜 80 % for a XGA device.
In many cases, the power efficiency of 10 〜 15 lm / watt in a projection system with three transmissive LCD panels has been routinely obtained.
Under such circumstance, 1000 〜 1500 lumens can be produced on a screen with a 100 W short-arc lamp.
>>563 〜
Linearly polarized light is required for most LC devices. A few polarization conversion devices have been invented to convert unpolarized light into linear one.
So that, the conversion efficiency reaches 70 〜 80 % . Furthermore, an array of microlenses is utilized to raise aperture ratio of a high resolution TFT-LCD panel.
The effective aperture ratio was improved to 〜 80 % for a XGA device.
In many cases, the power efficiency of 10 〜 15 lm / watt in a projection system with three transmissive LCD panels has been routinely obtained.
Under such circumstance, 1000 〜 1500 lumens can be produced on a screen with a 100 W short-arc lamp.
At that time ( 2003 〜 2004 ), as I worked in a certain company located in Fukaya-city of Saitama-prefecture in Japan ( ※ ) , I also had heard of the methodology.
※ TMD ;
a company which was founded on a joint investment of T and P
Strangely, though there are many research fruits about influences of light through liquid crystalline molecules on sub-consciousness, those results have been scarcely known.
>>576
If a laser-beam is applied to a compression wave inter-vertically, the compression wave plays the same role as a dif-fraction grating.
※ In these cases, ‘dif-fraction’ means the abbreviation of a different (≒ unusual) fraction’ implicating fractal dimensions or a rather unusual rate as a novel combination.
>>577
Namely, a certain fundamental experiment had been performed with a rather dated method,
so that an explosive accident was caused by the experiment and plural members who took part in the experiment were killed due to the explosive accident.
а
>>576>>577>>578
That is, those accidental cases show that basic experiments including acoustic-optical spectrometry were carried out around the region the end of the 1970’s 〜 the beginning of the 1980’s .
Indeed, we also heard that the fellows habitually undesirable advertisements including unreliable ones on the net would fight against the world as their enemies from now.
一
>>580
Besides, it’s probable that bad influences called Kodoku (蠱毒) brought through an obscure assassin such as 酒乱・大西共産党 ( the Great Western Communist Party as a Hopeless Alcoholic ) have considerably affected those fellows so as to make them misbehave.
