White point compensated leds for liquid crystal displays

FIELD: physics, optics.

SUBSTANCE: backlight for a colour liquid crystal display includes white light LEDs formed using a blue LED with a layer of red and green phosphors over it. In order to achieve a uniform blue colour component across the surface of a liquid crystal display screen and achieve uniform light output from one liquid crystal display to another, the leakage of blue light of the phosphor layer is tailored to the dominant or peak wavelength of the blue LED chip. The backlight employs blue LED chips having different dominant or peak radiation wavelength.

EFFECT: different leakage amounts of light through the tailored phosphor layers offset the attenuation on wavelength of the liquid crystal layers.

15 cl, 13 dwg

 

SCOPE

The present invention relates to a device backlight for liquid crystal display (LCD) displays and, in particular, to devices backlight for LCD displays that use light emitting diodes are white light.

The LEVEL of TECHNOLOGY

Figure 1 illustrates one type of color LCD display, operating at transmission.

Figure 1 is a liquid crystal display 10 includes Sydnaya the white light source 12, which provides back-lighting on the top layers of the LCD display. Sydnaya the white light source 12 has certain advantages over traditional fluorescent lamps, such as size, reliability and no need to use high-voltage power source.

In the not-too-small display device backlight typically use multiple Seeds white light for a more uniform distribution of light along the bottom layers of the LCD display and ensure the required level of brightness. For devices backlight small and medium-sized LCDS, LEDs, white light can be optically connected to one or more ends of the transparent fibers that are uniformly emit light from its upper surface. Light from a variety of Seeds, sometimes mixed within the light guide. For back illumination and medium to large LCD displays on the bottom surface sutomatically prism can be installed grid of LEDs white light. Over the outlet of the light guide or prism placed the diffuser film brightness intensifier or film amplifier dual brightness to mitigate or direction of light to illuminate the layers of the LCD display. Designers are always trying to bring all weekend luminosity of the LEDs white light to one target white point so that the device backlight issued uniform "white point" across the surface of the backlight device.

Layer 13 figure 1 represents lit with the end face of the optical fiber, and used in practice of any kind of mixing and optics (mixing prism, a diffuser film amplifier brightness, film amplifier dual brightness and so on). The combination of the light source 12 and the optical fiber with mixing optics (layer 13) is called next device 14 backlight.

Polarizing filter 15 linearly polarizes the light. After that polarized light is transmitted into the grid 16 of the transparent thin-film transistors with one transistor for each of the "sub-pixels" - red, green, and blue. A set of closely spaced from each other of the red, green, and blue sub-pixels is called a white pixel, the color "dot" which is a combination of three sub-pixels. If all RGB subpixels excited this point generates white light. Lattice thin film TRANS is well-known stores. Lattice thin-film transistor controlled by the controller 17 of the LCD display.

Above the grille 16 thin-film transistor is the liquid crystal layer 20, and above the liquid crystal layer 20 is a transparent conductive layer 22 connected to ground. In one type LCD, an electric field is fed through the zone of sub-pixels liquid crystal layer 20 causes rotation of the polarization plane of light passing through this zone of sub-pixels perpendicular to the input polarization. The absence of an electric field in the area of sub-pixels liquid crystal layer 20 causes the ordering of liquid crystals without affecting the polarization of the light. Management of local electric fields across the liquid crystal layer 20 is selectively zapisywanie transistors. Each area of the liquid crystal layer associated with the user, typically called a shutter, since each shutter controls the passage of the output of the display from 0 to 100% (assuming no losses in the system) of the input light. The liquid crystal layers are well known and are commercially available.

Polarizing filter 24 transmits only light polarized orthogonal to the light emerging from the polarizing filter 15. Therefore, the polarizing filter 24 passes only the light which has been polarization application : the van area of the excited sub-pixels in the liquid crystal layer 20, and absorbs light that passes through the unexcited areas of the liquid crystal layer 20. The magnitude of the electric fields across the liquid crystal layer 20 control the brightness of individual R-, G - and B-component and thereby create any color in each pixel of the reproduced image.

Other types of LCD displays transmit the light only through the unexcited pixels. In the following LCDs are used polarizers with different polarization. In some types of polarizers passive grid conductors are replaced by bars 16 of the thin-film transistors, in this case the excitation conductor of a certain number and conductor particular column activates the area of the pixel of the liquid crystal layer at the point of their intersection.

After that, the light passing through the polarizing filter 24, is filtered RGB pixel filter 25. This RGB pixel filter 25 may be located in other places in the foot, such as somewhere above or below the liquid crystal layer 20. RGB pixel filter 25 may consist of a layer of the red filter layer, a green filter layer and a blue filter. Layers can be stacked in the form of thin films. As an example, a red filter layer contains a set of zones of the red color filter, determining the area of the red sub-pixels of the display. Similarly, layers of green and blue filters allow to pass in the areas of green and blue sub-pixels only green and blue light. Accordingly, the RGB pixel filter 25 provides a filter for each of the sub-pixels R, G and B in the display.

RGB pixel filter 25 performs internal filtering at least two thirds of the total light reaching, since each of the filtering area of the subpixel allows the passage of only one of the three primary colors. This is an important factor usually weak efficiency of LCD displays of the prior art. The total transmittance of the layers of the LCD screen on the back of the backlight 14 is on the order of 4-10%.

One type of Sid white light is shown in figure 2. LED 30 has "inverted" Sydnaya crystal formed from the active semiconductor light-emitting layer 32 located between the layer 33 of p-type and a layer 34 of n-type. Optionally, the substrate cultivation (e.g., sapphire) is removed. Sydnaya crystal emits blue light. Conventional materials for Sydnaya crystal are GaN and SiC. Examples of the formation of such Seeds is described in U.S. patent No. 6649440 and 6274399, both of which are assigned to Philips Lumileds Lighting and is included here as a reference.

Sydnaya crystal placed on abaporu 36, made of any suitable material, such as ceramics or silicon. This Sydnaya crystal has a lower metal contacts 38 that are associated with the United with subparas 36 steel supports 40 through the Golden Shari and 44. Intermediate items across subpara 36 connected with the metal supports on the bottom surface of subpara 36, which are connected with the metal pins on the circuit Board 46. The metal terminals are connected with other Seeds or power source.

Because Sydnaya crystal emits only blue light to obtain white light must be added the red and green light components. These red and green components are provided with a layer 48 of the phosphor, which contains red and green phosphors or contains a yellow-green phosphor (e.g., AIG). The layer 48 of the phosphor can also cover the sides Sydnaya crystal. There are many known ways of imposing a layer of phosphor on the blue crystal to produce white light.

Layer 48 phosphor allows for a certain percentage passing blue light SIDA. Some part of the blue light is absorbed by the phosphor and re-emitted in the form of a red or green light, or yellow-green light). The combination of blue light and emitting phosphor gives white light. The target white point is achieved by the choice of the densities of the particles of the phosphor layer, the relative amount of the phosphor and the thickness of the phosphor layer.

Even if supplied by the manufacturer blue LEDs can be performed using the same surface is uraemic procedures the dominant wavelength of blue LEDs vary from batch to batch and even within the same party. When application-specific dominant wavelength is important manufacturer excites blue LEDs and measures their dominant wavelengths, and then groups the LEDs in accordance with their wavelengths. Dominant wavelength may be different on 40 nm, and each group typically can include LEDs within the range of 5-8 nm (i.e., deviation of 2.5-4 nm from the Central wavelength group). The normal range for the dominant wavelength of the blue LEDs used as the Led backlight is 420-460 nm.

Previously, the designers of the device backlight tried to lead white dots all of the Led devices of the rear lights are the same, so that the human eye perceived the same white color emitted over the entire surface of the rear lights, and when switching from one device backlight to another. This can be made precise selection of crystals and exact reproducibility of the characteristics of the phosphor layer for each crystal. It is wasteful to those Sydnaya crystals, which do not correspond to the dominant wavelength. Alternatively, the characteristics of the phosphor layer can be tailored to suit the group blue Sid, so that the resulting white point for each Sid with what fell from the only target white point. All such white color for the human eye will seem the same.

The authors of the present invention measured the attenuation of light by the layers of the display depending on the wavelength and determined that the attenuation of light in the visible range of wavelength is changed. This change in the wavelength range of blue color the most. The light attenuation is due to the combined attenuation of the polarizers, the electrodes of indium oxide and tin (grounded transparent layer), a liquid crystal layer and RGB filters. In addition, there are also non-uniform attenuation of the fiber (if used), the diffuser (if used) and the film enhance the brightness (if used).

The inventors have found that due to changes in light attenuation layers of the LCD depending on the wavelength, even if the white point of the Led backlight is adjusted by forming characteristics of the phosphor under each group of blue LEDs, the measured color output LCD unstable on the surface of the LCD display, as when all pixels are fully enabled to produce a high-quality display with white light.

Therefore, it is necessary Sydnaya device backlight, which would ensure that the color output of the LCD display was standing on the surface of the LCD display and from one LCD to another.

The INVENTION

The attenuation of light by the layers of the LCD display in the band of wavelengths of the blue color increases as the wavelength of the blue color becomes less. The inventors have found that in order to achieve a uniform blue color components on the surface of the screen of the LCD display white point (correlated color temperature) of all the different LEDs white light must not meet one another when the dominant wavelengths of blue Sydnaya crystals are different. It goes against common object constructors backlight LCD display.

To offset the attenuation versus wavelength layers of the LCD display, blue Sydnaya crystals, which emit a relatively short dominant wavelength of the blue color, have layers of phosphor selected so that they allow more "flow" of the blue color in comparison with layers of phosphors for crystals of blue LEDs, which emit longer dominant wavelength of the blue color. In other words, since the liquid crystal display weakens the shorter blue wavelength to a greater extent than the longer "blue wave", then to "blue" the output signal of the LCD display would be the same regardless lit if the display is back-lit using blue LEDs with short waves or COI is whether the blue Seeds with long waves. On the amount of blue light cast from the back side of the LCD, affects only "leak" through the phosphor.

Although in the above examples for the characteristic blue Seeds are dominant wavelength, may be used instead of the wavelength of maximum radiation.

To get to different groups selection of different size "leaks" through the phosphor layer to fit the thickness of the layer of phosphor and/or the density of the phosphor particles. To a lesser extent the relative percentage of red and green phosphors may be adjusted due to the different excitation energy applied to the crystal Sid.

To obtain a uniform output of the red and green light Sid the phosphor layer should, however, serve and red and green light components of the white light. As the weakening of the led red and green light with wavelength changes slightly, the values of the red and green light component SIDA white light can be constant for all Seeds.

Because different LEDs white light used for the rear lights will emit essentially equal components of red and green light, but depending on the dominant wavelength of each Sydnaya crystal will emit different levels of brightness blue light, in the case when the rear under the branches will be used LEDs from different groups, white dots of different Seeds will be different, causing the appearance of non-uniformity of the output of the illumination device backlight on its surface. This is particularly evident in those areas of the backlight, where the light from different LEDs not mixed thoroughly. The LEDs are white light emitting blue color with a shorter dominant wavelength, will seem more blue than white LEDs light emitting blue color with longer dominant waves.

If each device backlight would contain only the LEDs white light using all of the blue LEDs from the same group, then a white dot around the device backlight would be essentially the same. The advantage of the present invention in this case consists in the fact that the output color of the Led will be constant from one Sid to another regardless of which of the groups of LEDs was used to install them in device backlight.

Such management white dots of the Led backlight acceptable for those devices backlight, in which the LEDs are white light is installed on an end face of the light guide, and for those devices backlight in which these LEDs are located immediately behind the layers of the LCD display.

In one embodiment, the phosphor for a specific crystal blue SIDA applied over the crystal forming what repressively phosphor on top of the crystal. This is done by preparing a suspension of phosphor powder in the liquid binder substance, such as silicon with a high refractive index, then filled with a mixture of phosphor/binder of all cavities form. After this, in the form attached fixed on the wafer subpara blue LEDs so that each blue LED was immersed in the material of the phosphor/binder filled cavities. Then the material of the phosphor/binder" cures, after which the wafer subpara separated from the form. Preferably, all blue LEDs, filling wafer substrate, were selected from the same group, so that the material of the phosphor/binder and/or characteristics of the forms were identical for all Sydnaya crystals.

In another embodiment, the phosphor plate fixed on top Sydnaya crystals, adjusted in accordance with the group Sid.

The top node of the crystal/the phosphor can be prepressure clear lens for improved light extraction and to protect Sid.

BRIEF DESCRIPTION of DRAWINGS

Figure 1 is a conventional view of a conventional LCD display with white Sidney back-lit.

Figure 2 is a view in cross section of one type of Sid white light using crystal blue SIDA and the phosphor layer on the supplements I the red and green component.

Figure 3 is a graph showing characteristics of the RGB filter in a conventional LCD display simultaneously with the measured output of the LCD display blue, green and red light, indicating that the measured output does not match the characteristics of the RGB filter, and showing that the blue light of shorter wavelengths is attenuated stronger than the blue light of longer waves.

Figure 4 is a graph showing changes in v' components in the standard chromaticity diagram of the CIE u'v' of the wavelength of blue color.

Figure 5 is a graph of the output of the spectral distributions of two different LEDs white light, in which the white dots are different, but the color output of the LCD display when using the device backlighting of any of these Seeds is the same.

6 is a view in cross section of the LCD, which includes the layers of the LCD display and the backlight device of the LEDs white light, in which the LEDs are white light are arranged in a grid directly behind the layers of the LCD display.

Fig.7 is a view in cross section of the LCD, which includes the layers of the LCD display and the backlight device of the LEDs white light Led white light attached to the end face of the optical fiber to create a backlight.

Figa-8C illustrate a two-step process of re-pressing for stamping under ganago layer of phosphor over the blue Sydnaya crystal, followed by forming on the crystal and the transparent phosphor lens.

Figa and 9B illustrate the mounting plate fitted over the blue phosphor Sydnaya crystal, followed by forming on the crystal and the transparent phosphor lens.

Figure 10 is a block diagram that defines the different steps used to manufacture the LCD using Led white light in accordance with one embodiment of the present invention.

Elements that are the same or identical, marked by the same reference position.

DETAILED description of the INVENTION

The present invention can use the regular blue crystals Seeds, such as blue LEDs on AlInGaN, manufactured by the assignee of the present invention. The examples here "inverted" Sydnaya crystal is used for ease of description. Crystal blue Sid may be the same as shown in figure 2, with the remote substrate growth.

Examples of the formation of the LEDs is described in U.S. patent No. 6649440 and 6274399, both of which are assigned to Philips Lumileds Lighting and is included here as a reference.

It is assumed that the blue LEDs for use in devices of the rear lights have a dominant wavelength of about 440 nm. However, for reasons inherent in the nature of the manufacturing processes of LEDs, the dominant wavelengths are typically in the range between, which is but 420 and 460 nm. Crystals of blue LEDs then supplied and tested measuring device to determine the dominant wavelength of each Sid. Thereafter, the crystals are sorted physically, or save them after testing provisions Sydnaya crystal wafer substrate in the memory. Each group may include crystals having a dominant wavelength in the approximate range of 2-4 nm relative to the specified dominant wavelength group.

The term "dominant wavelength" refers to a single wavelength, which is perceived by the human eye and is defined as the wavelength of monochromatic light, which has the same apparent color as the light source. If the color of a single wavelength (X nm) is indistinguishable from the color of this CID, then the LED has a dominant wavelength of X nm.

Another way to sort of blue LEDs is to measure the wavelength of their emission maximum. The wavelength of the emission maximum is defined as a single wavelength, in which the range of the measured radiation of the light source reaches its maximum. It does not represent a radiation light source as perceived by the human eye. Accordingly, dominant wavelength, and the wavelength of maximum radiation can be used to sort the blue Seeds, although in primarygrade be used dominant wavelength.

Characteristics of attenuation of radiation by wavelength specific LCD display for use with the backlight device shall be determined by application of the light source with a broad spectrum to the rear surface of the layers of the LCD display followed by measuring the light output of the LCD on different wavelengths.

Figure 3 is a simplified picture of the characteristics of the light attenuation RGB color filters (bold line) in a particular LCD display. Along with the stored relative characteristics of the filter, the values are normalized so that the maximum of the red color of the red filter are given to 1.0. In the ideal case, the filters would have to give the steady weakening in a narrow frequency band, and then a rapid blockage. However, in the actual liquid crystal display characteristics reveal a strong dependence on the wavelength.

As can be seen from the graph, line 50 blue filter indicates the minimum attenuation of blue light at a wavelength of 440 nm, the dashed line 52 green filter indicates the minimum weakening of the green light at a wavelength of 520 nm, and the line 54 of the red filter is essentially unchanged. In the ideal case, the amount of blue light through a blue filter is constant throughout the range of dominant wavelengths of blue crystals Sid, however, this is not what.

Figure 4 shows the attenuation characteristic of the LCD display in the range of blue light, which is consistent with figure 3. Figure 4 for a particular LCD display built the change of the wavelength of v' color of light directed to the liquid crystal display, the color of light emitted from the LCD display, where v' is pending on the y-axis value by the standard chromaticity diagram of the ice. Standard chromaticity diagram of the CIE shows the corresponding colors at the intersection of the values u' and v'. In the ideal case, the change in v', due to the layers of the LCD, it would be the same for all wavelengths. A greater change in the value v' for short wavelength blue range is correlated with greater weakening of the liquid crystal display and the "shift up" on the chromaticity diagram of the CIE color other than blue.

Going back to figure 3, it measured the light output of the LCD screen for each wavelength shows a more fine lines 56, 58 and 60. This measurement can be performed by the lighting of the layers of the LCD display at the rear of the backlight light source with a wide range of fully include only pixels of the same color (red, green, or blue), and then using an optical measuring apparatus for measuring light intensity on the wavelength of that same color. The output line 58 green light scaling etc is led to the line 52 green filter, but the relative magnitudes of the output line 56 of the blue light, the output line 58 of the green light and the output line 60 of the red light saved. The measured output line 56 of the blue light with decreasing wavelength, as shown, is increasingly at odds with the line 50 blue filter. The output line 58 green light coincides with the characteristic green filter. The output line 60 of the red light to be somewhat attenuated by the layers of the LCD, but since the output line of the red light is "flat", the weakening of the layers of the LCD screen around the red range is slightly dependent on the wavelength.

Due to the dependence of the attenuation characteristics of the layers of the LCD display from the wavelengths of the white point (white dots) LCD display will not(ut) remain the same (the same)as a white point (white dots) back light, when all the red, green and blue pixels will be included at the same time.

Vertical dotted lines 64-68 represent the Central wavelength of the five different groups sort blue Sydnaya crystals, determined either by measurement of dominant wavelength or wavelengths of maximum radiation. As can be seen from figure 3, the liquid crystal display reduces blue light group 64 is much stronger than the blue light group 68. This means that if the blue LEDs all groups will have the same transmittance of blue light, then nablyudaemymi light, out of the LCD display when it is illuminated by the led group 64, will be less bright than the output blue light, when the display is illuminated by the led group 68. This will cause a change coming from the LCD display blue light on the display surface, because the device backlight does not produce uniform mixing of all of the light from different LEDs white light across its output surface. For the device backlight with edge lighting especially is written, the situation on the edges of the backlight, where the LEDs, and the light is not fully mixed. For systems with mixing prisms, in which the LEDs are distributed directly from the back side of the LCD, the color unevenness will occur across the screen near each Sid.

To compensate for wave attenuation characteristics of the layers of the LCD layer of phosphor on a blue Led is "fit" each group of blue LEDs, in order for groups with shorter wavelengths allow more blue light. Due to the phosphor layer red and green light components of the white light should essentially remain unaffected. Thus, the LEDs white light formed by using short-wavelength blue LEDs from the group of 64, because through the liquid crystal display will be more inego light - for the human eye will be seen more blue compared to the LEDs white light formed using longer-wavelength blue LEDs group 65-68. White light from the LEDs will be formed by the use of blue Sydnaya crystals of group 68, will seem less blue than the light from all the other LEDs white light group 64-67.

Adjusting the transmittance of blue light can be performed by changing the density of the phosphor particles in a binder substance or doing phosphor layer thinner.

Figure 5 is a graph representing the light emission from two different LEDs white light, in which the phosphor layer was fitting for the correction value of the transmittance of blue light. White light is not passed through the liquid crystal display. Curve 72 shows the relative brightness of the emitted light at different wavelengths for Sid white light using a blue LED with a shorter dominant wavelength or wavelength of the emission maximum. Curve 74 shows the relative brightness of the emitted light at different wavelengths for Sid white light using a blue LED with a longer wavelength. If these LEDs white light were used to backlight LCD display, white dot LCD display (all pixels on) for both Seeds would be exactly the same,even though the white point Sid with emission curve 72 at the output of the device backlight seemed to be more blue. It should be noted that the outputs of the green and red light of the Led white light in figure 5 are the same, since the phosphor layers on both blue LEDs generate the same green and red components.

Therefore, when using the present invention, the device backlight with LEDs white light formed using blue LEDs from different groups would have different white point on its surface.

If the device backlight was filled with white LEDs formed using blue LEDs from the same group, then the white dot on the entire surface of the backlight device would be the same. The benefits of the present invention in this case consists in the fact that the output color LCD displays will be the same from one LCD to another regardless of which group of Seeds was used to fill the device's backlight.

Fig.6 shows the compensated LEDs white light 76, such as LEDs white light presented on figure 5, placed on the bottom reflective mixing prism 78 backlight. It is assumed that the crystals of the blue LEDs used for the formation of the LEDs 76 were from different groups, so when is that the white point of the Led 76 will be different. The light from the LEDs 76 are additionally mixed in the diffuser 80. Although the light from the LEDs in the backlight device (consisting of the LEDs 76, prism 78 and diffuser 80) to some extent mixed, the radiation from the backlight is still unevenly on the surface of the device backlight because of the different white points of the LEDs 76. However, the color output layers 82 of the LCD display in the wavelength range of blue color will be essentially uniform across the LCD display due to the adjustment layer (s) red and green phosphors. Instead, it can be used a layer of yellow-green phosphor YAG, and the phosphor layer is adjusted, as described above, to adjust the magnitude of the transmittance of blue light. Layer 82 Sid may be as shown in figure 1

Since the materials of the device backlight themselves in varying degrees to loosen the waves of blue light, the attenuation of blue light should also be taken into account when fitting phosphor layer.

7 shows another type of LCD display that uses the light pipe backlight 84, such as made of material emission spectra obtained for pure. To achieve a uniform light reflection up to cover the rear surface of the LCD display 82 can be used prism or the application of roughness on the bottom surface of the backlight device. As upominalos is earlier, although the light from the LEDs to some extent mixed in the device 84 backlight, the radiation from the device 84 backlight still unevenly across the surface of the rear lights from the LEDs 76. However, the color output layers 82 of the LCD display in the wavelength range of blue color will be essentially uniform throughout the liquid crystal display due to the adjustment layer (s) red and green phosphors. Since the attenuation of blue light material emission spectra obtained for pure wavelength is changed, the characteristic of the attenuation of blue light should also be taken into account when fitting phosphor layer.

Figa-8C illustrate one method of forming the fitting layer of phosphor over the crystal blue SIDA. On figa on the "wafer" 86 subpara has attached to it the lattice of crystals 88 blue Seeds, preferably from the same group. On the "wafer" 86 may be installed more than 100 Seeds. "Wafer" 86 subpara can be ceramic with metal plates/pins associated with each Sydnaya crystal 88.

Form 90 has a cavity 91 corresponding to the desired shape of the phosphor layer over each Sydnaya crystal 88. Form 90, preferably made of metal. As recapitalise layer on top form 90 may be placed in a very thin nepriklausomas film or, if necessary, FD is mA 90 may have a non-sticky surface layer.

The cavity 91 of the form 90 is filled thermoset mixture of particles 92 of the red and green phosphor with silicon binder substance 94. Silicon has a large refractive index (i.e., 1,76)sufficient to significantly increase the light output from SIDA AlInGaN. The density of the particles 92 phosphor and/or the thickness of the phosphor layer are selected so as to achieve the desired value of the transmittance of the blue light used for Seeds from a specific group, as described previously.

"Wafer" 86 and 90 are connected together, and between the edges "waffles" 86 and forms 90 creates a vacuum seal. Therefore, the crystal each Sid is inserted into the phosphor mixture, and the mixture itself is under compression.

After that, the form 90 is heated to a temperature of about 150C (or to another desired temperature for the time required for curing of the binder material.

After this "wafer" 86 from the form 90 is disconnected. The binder material can then be further overiden by heating or ultraviolet radiation.

Figv over each of the LEDs with matched layer 95 phosphor, prepressure transparent silicon lens. The mold cavity 96 filled with liquid or melted silicon 98, and "wafer" 86 and form 96 are connected together, as described above. After that, the silicon 98 cures, and "wafer" 86 and form 96 sever the I, in the resulting design, shown in figs, in which on each of Sydnaya crystals and luminophore layers formed of a transparent lens 100. Then "wafer" 86 subpara is cut (for example, along the dotted line) to separate the Seeds of white light. After this subpara Seeds of white light can be placed on a printed circuit Board, as shown in figure 2, together with all the other white LEDs for use in the backlight device.

For more details on forming the pressing phosphor and lenses can be found in the patent publication U.S. 20080048200, entitled "LED with phosphor mosaic and prepisovanie the phosphor in the lens" Gerd Mueller, etc. included here as a reference.

As shown in figa and 9B, instead of forming a layer of a phosphor layer of the phosphor may be in the form of plates 103 and attached to the upper surface Sydnaya crystal 88 using a thin layer of silicon, similar to the design shown in figure 2. The thickness of the plates 103 and/or the density of the particles of the phosphor are selected for each group Sydnaya crystal blue LEDs to pass through itself the right amount of blue light. One way of forming a sheet of ceramic phosphor is sintering of the powder particles of the phosphor material using heat and pressure. Percent the blue light, passing through this plate depends on the density of the phosphor and the thickness of the plate, which can be precisely controlled. Another method of forming a thin sheet of phosphor is rolling phosphor "test" in a thin sheet, and then drying. The formation of such plates ceramic phosphor is described in patent publication U.S. 20050269582, entitled "Luminescent ceramics for light-emitting diode" Gerd Mueller, etc. included here as a reference.

Then over Sydnaya crystal and the phosphor plate is molded lens 100, using the same process as described with reference to figv and 8C.

Clear lens increases light output, and also protects the LED and the phosphor.

Figure 10 is a block diagram showing the various stages of one variant of the present invention.

At step 111 to determine the attenuation characteristics of the layers of the LCD display and materials of the device the rear of the backlight depending on the wavelength of blue light. If the back-light makes a negligible attenuation characteristics of the device backlight can be neglected.

At step 112 measure the dominant wavelengths of crystals of blue LEDs, and the LEDs are sorted according to their dominant wavelengths.

At step 113 define the required features is specific (for example, the density, thickness ratio) of the red and green phosphor layers over the blue Sydnaya crystal blue Sydnaya crystal of each group to obtain the output of the white light from the LEDs will be necessary to achieve uniform color output LCD display, taking into account the characteristics of the weakening of the layers of the LCD display and materials of the device the rear of the backlight depending on the wavelength of blue light. This determination may be performed using any simulation or empirical methods.

At step 114 over the blue Sydnaya crystal groups provide a layer of red and green phosphor (or layer AIG), adjusted to this group. This can be done by attaching over Sydnaya crystal fitting phosphor plate (step 115) or Overlaminating over Sydnaya crystal fitting phosphor layer (step 115), or using any other technique.

At step 117 over the crystal and the phosphor is formed into the transparent lens to enhance light output and protection Sid and phosphor.

At step 118, the resulting LEDs white light is used in the backlight device, in order in the color liquid crystal display to achieve a uniform output green, red and blue light for each liquid crystal display, and DL is achieving a uniform color from one LCD to another.

Although conventional LCD display will loosen the blue light of shorter wavelengths more than longer-wavelength blue light, the present invention is widely applicable in those liquid crystal displays, which have irregular wave characteristics attenuation of blue light.

Although there have been shown and described a specific embodiment variants of the present invention, specialists in the art will be obvious changes and modifications can be made without deviating from the present invention in its broader aspects, and therefore, the attached claims are intended to limit them within a certain amount of invention all such changes and modifications as appropriate the true nature and scope of the present invention.

1. The method of forming the system of the LCD (LCD), using light-emitting diodes (LEDs), which emit white light, this method includes:
characterization of attenuation depending on the wavelength of blue light at least layers of the LCD display, used for the formation of a color display, in the range of visible wavelengths of blue light of shorter wavelengths is attenuated by the layers of the LCD display is different from the blue light of longer waves;
measurement of dominant wavelength ridlin wave radiation maximum crystal blue LEDs;
providing layers of phosphor over the crystal blue LEDs, these phosphor layers allow blue light emitted from the crystal blue LEDs to pass through layers of phosphor, and the amount of passage of blue light through the layers of the phosphor is controlled by the correction characteristics of the phosphor layers, and the magnitude of the passage of blue light through the phosphor layer over the crystal blue Sid corresponds to the dominant wavelength or wavelength of the emission maximum of the crystal blue SIDA, and the phosphor layer for the first crystal blue Sid, having a first dominant wavelength or the wavelength of maximum radiation is adapted to allow the passage of a larger amount of blue light compared with the phosphor layer to the second crystal blue Sid, having essentially different dominant wavelength or the wavelength of maximum radiation to at least partially displace the characteristics of attenuation depending on the wavelength of blue light layers of the LCD display;
the light emitted by the combination of the blue light passing through the phosphor layer and the light emitted by the phosphor layer is a white light with a white point at least partially dependent on the amount of blue light transmitted through the phosphor layer and the blue crystals Seeds, with the provided them with layers of phosphor, are the LEDs white light, and
providing at least one of the LEDs white light as a light source for a backlight to illuminate the layers of the LCD display.

2. The method according to claim 1, further comprising connecting at least one SIDA of white light from the backlight device.

3. The method according to claim 2, further comprising connecting the device backlight to the layers of the LCD to illuminate the layers of the LCD display.

4. The method according to claim 1, wherein providing at least one of the LEDs white light as a light source for the backlight comprises providing a variety of LEDs white light as a light source, with LEDs, white light into the many Seeds provided as a light source for backlight, have different white points.

5. The method according to claim 1, in which the phosphor layers include particles of red and green phosphor.

6. The method according to claim 1, in which the correction characteristics of the phosphor layers includes the correction of the density of the phosphor particles, and the smaller the density of the phosphor particles permit the passage through the layer of phosphor greater amount of blue light.

7. The method according to claim 1, in which the correction characteristics of the phosphor layers includes the correction of the thickness of the phosphor layers, and thinner with the second phosphor permit the passage through the layer of phosphor greater amount of blue light.

8. The method according to claim 1, wherein providing the layer of phosphor over the crystal blue LEDs includes Overlaminating layer of phosphor over the crystal blue Seeds.

9. The method according to claim 1, wherein providing the layer of phosphor over the crystal blue LEDs includes mounting plates phosphor above the crystal blue Seeds.

10. The method according to claim 1, further including:
connecting at least one SIDA of white light to the backlight device,
connecting the device backlight to the layers of the LCD to illuminate the layers of the LCD display; and
excitation of at least one SIDA of white light.

11. Lighting system, comprising:
many light-emitting diodes (LEDs) white light, and each LED white light contains Sydnaya crystal that emits blue light, and the phosphor layer, the light emitted by the combination of the blue light passing through the phosphor layer and the light emitted by the phosphor layer is white, with a white point at least partially dependent on the amount of blue light transmitted through the phosphor layer, and
the backlight device containing LEDs white light, and a device for mixing light, the backlight device is intended for rear illumination of the layers of the LCD display, while the layers of the LCD display are ner is numerou characteristic of attenuation depending on the wavelengths of blue light, in the range of visible wavelengths of blue light of shorter wavelengths is attenuated by the layers of the LCD display is different from the blue light of longer waves;
thus the value of the passage of blue light through the phosphor layer on the crystal Sid, essentially corresponds to the dominant wavelength or wavelength of the emission maximum crystal SIDA, and the phosphor layer for the first crystal Sid having a first dominant wavelength or wavelength of the emission maximum, permit the passage of a larger amount of blue light in comparison with the phosphor layer to the second crystal Sid, having essentially different dominant wavelength or the wavelength of maximum radiation to at least partially displace the characteristics of attenuation depending on the wavelength of blue light layers of LCD display.

12. The system according to claim 11, further containing layers of the LCD, United backlit.

13. Illumination system for color LCD display formed using the following process:
characterization of attenuation depending on the wavelengths of blue light, at least, of the layers of the LCD display, used for the formation of a color display where in the range of visible wavelengths of blue light of shorter wavelengths is attenuated by the layers of the LCD display is different from blue light Bo is her long waves;
measurement of dominant wavelength or wavelengths of the emission maximum crystal blue LEDs;
providing layers of phosphor over the crystal blue LEDs, these phosphor layers allow blue light emitted from the crystal blue LEDs to pass through layers of phosphor, and the amount of passage of blue light through the layers of the phosphor is controlled by the correction characteristics of the phosphor layers, and the magnitude of the passage of blue light through the phosphor layer over the crystal blue Sid corresponds to the dominant wavelength or wavelength of the emission maximum blue crystals SIDA, and the phosphor layer for the first crystal blue Sid, having a first dominant wavelength or the wavelength of maximum radiation is adapted to allow the passage of a larger amount of blue light compared with the phosphor layer to the second crystal blue SIDA has a different dominant wavelength or the wavelength of maximum radiation to at least partially displace the characteristics of attenuation depending on the wavelength of blue light layers of the LCD display;
the light emitted by the combination of the blue light passing through the phosphor layer and the light emitted by the phosphor layer is a white light with a white point at least partially dependent on the amount of si is its light, passing through the phosphor layer and the blue crystals Seeds that have associated phosphor layers are LEDs white light, and
connecting the many Seeds of white light to the device mixing of light for the formation of the back to illuminate the layers of the LCD display.

14. Illumination system according to item 13, in which the LEDs are white light in a set of LEDs connected to the mixing device of light have different white points.

15. Illumination system according to item 13, in which the phosphor layers include particles of red and green phosphor.



 

Same patents:

FIELD: physics.

SUBSTANCE: liquid crystal display device (100) of the present invention includes a liquid crystal display panel (10) and a lateral illumination unit (20) which emits light from a position which is lateral with respect to the panel (10). The panel (10) includes a front substrate (1), a back substrate (2) and a light-diffusing liquid crystal layer (3). The unit (20) includes a light source (7), which is situated in a position which is lateral with respect to the panel (10), and a light-guide (6), having a light-output surface (6b) through which light emitted by the light source (7) as well as light incident on the light-guide (6) is emitted towards the end surface (1a) of the substrate (1). The surface (6b) is slanted relative a direction which is vertical with respect to the front surface (1b) of the substrate (1), such that it faces the back surface of the panel (10).

EFFECT: preventing generation of a bright line in the panel.

3 cl, 6 dwg

FIELD: electricity.

SUBSTANCE: in carrier pin (11) used for support of optical elements (43-45) though which part of light passes from light-emitting diode (24) a part of peak (14) contacting with light-diffusing plate (43) is formed of light-reflective material while a part of rack (12) supporting peak (14) is formed of light-transmitting material.

EFFECT: eliminating mom-uniformity of lighting.

12 cl, 13 dwg

FIELD: physics.

SUBSTANCE: backlight unit (49) of a display device (69), having a liquid crystal display panel (59), equipped with a base (41), a diffusing plate (43) mounted on the base, and a light source which illuminates the diffusing plate with light. The light source has a plurality of light-emitting modules (MJ) which include a light-emitting diode (22) which serves as a light-emitting element, and a divergent lens (24) covering the light-emitting diode. The light-emitting modules are placed on a grid on the base supporting the diffusing plate. Carrier pins (26) for mounting the diffusing plate are located on points on the base. The carrier pins are placed on sections of lines linking neighbouring pairs of light-emitting modules.

EFFECT: eliminating non-uniformity of luminance.

10 cl, 14 dwg

FIELD: physics.

SUBSTANCE: backlight unit (49) of a display device (69), having a liquid crystal display panel (59), has a base (41), a diffusing plate (43) which is supported by the base, and a point light source for irradiating the diffusing plate with light. The point light source has a light-emitting diode (22) mounted on a mounting substrate (21). A plurality of light-emitting diodes covered by divergent lenses (24) are provided. Optical axes (OA) of the divergent lenses are inclined relative the diffusing plate, and the divergent lenses, having different inclinations of optical axes, are placed randomly on the base. The divergent lenses, having optical axes that are inclined in opposite directions, are paired and the pairs are arranged in a matrix.

EFFECT: reduced non-uniformity of luminance and hue.

25 cl, 12 dwg

FIELD: electricity.

SUBSTANCE: lighting device 12 comprises multiple point sources 17 of light and a base 14, where point sources of light 17 are placed, which are classified into two or more colour ranges A, B and C, in accordance with light colours. Each colour range is defined by means of a square, each side of which has length equal to 0.01 in the colour schedule of light space of the International Lighting Commission 1931.

EFFECT: reproduction of light of practically even light.

26 cl, 15 dwg

FIELD: electricity.

SUBSTANCE: lighting device includes multiple LED 16, circuit board 17S LED, chassis 14, connection component 60 and reflecting plate 21. LED 16 are installed on circuit board 17S LED. Both plates 17S and 17C LED are attached to chassis 14. Connection component 60 is electrically connects circuit boards 17S and 17C LED between each other. Reflecting plate 21 is put on surface 17A of light sources installation. In the lighting device, connection component 60 is located on surface 17B of attachment of connection component of circuit board 17S LED. Surface 17B of attachment of connection device is opposite to the surface, on which reflecting plate 21 is put.

EFFECT: increasing brightness of reflected light.

23 cl, 22 dwg

FIELD: physics.

SUBSTANCE: device has a holder (11) which attaches a mounting plate (21) to a backlight base (41) while covering at least the edge (21S) of the mounting plate (21) on the backlight base (41), said edge being situated in the direction of the short side of the mounting plate. The surface of the mounting plate covered by the holder has a non-uniform reflection area which can be in form of a connector or a terminal.

EFFECT: improved uniformity of the amount of light from the backlight unit.

21 cl, 39 dwg

FIELD: electricity.

SUBSTANCE: back light unit (49) for display device (69) equipped with LCD panel (59) contains a frame (41), dissipating plate (43) supported by the frame and point light sources supported by mounting substrates (21) provided at the frame. Point light sources contain LEDs (22) installed at mounting substrates. Mounting substrates (21) are interconnected by connectors (25) thus forming rows (26) of mounting substrates (21). Varieties of rows (26) of mounting substrates (21) are located in parallel; a row (26) of mounting substrates (21) is formed by long and short mounting substrates (21) and location of such long and short mounting substrates (21) is changed to the opposite row-by-row. Positions of connectors (25) are not levelled in a straight line in direction of rows (26) of mounting substrates (21).

EFFECT: providing uniform brightness of the dissipating plate.

23 cl, 10 dwg

FIELD: electricity.

SUBSTANCE: backlighting unit (49) for a display device (69) equipped with a liquid crystal display panel (59) comprises a base (41), a diffusing plate (43), supported by means of the base, and point sources of light, supported by means of mounting substrates (21), provided on the base. Point sources of light contain modules of light emission (MJ). Mounting substrates are arranged in the rectangular area (41a) suitable for location of mounting substrates in it and arranged on the base. Gaps at the borders between mounting substrates do not stretch in any direction along long sides and/or in direction along short sides of the rectangular area, in order to provide for the possibility to see the rectangular area from the edge to the edge.

EFFECT: achievement of homogeneity of reflection ratio.

16 cl

FIELD: physics.

SUBSTANCE: liquid crystal display device includes a first polariser, a second polariser facing the first polariser, a liquid crystal display panel provided between the first polariser and the second polariser, and a first phase plate and a second phase plate provided between the first or second polariser and the liquid crystal display panel. The display panel has a pair of substrates and a liquid crystal layer placed between the pair of substrates, which includes homogeneously aligned liquid crystal molecules. The phase plate includes a liquid crystal film placed in a position where the nematic liquid crystal is hybrid-aligned. Phase difference in the perpendicular direction of the element situated between the first and second polarisers, excluding the liquid crystal layer and the first phase plate, is 120 nm or greater.

EFFECT: reduced inversion of the gray gradation scale in a position where a colour close to black is displayed.

19 cl, 116 dwg

FIELD: mechanical engineering.

SUBSTANCE: device has signal form generator, power amplifier and electromechanical block, including first fixed magnetic system and first coil of current-conductive wire, additionally included are integrator and corrector of amplitude-frequency characteristic of electromechanical block, and block also has second fixed magnetic system and second coil of current-conducting wire, rigidly and coaxially connected to first coil. Connection of first and second coils with fixed base is made in form of soft suspension with possible movement of first and second coils, forming a moving part of modulator, relatively to fixed magnetic systems, while output of said signal shape generator is connected to direct input of integrator, inverse input of which is connected to speed sensor of moving portion of modulator, output of integrator is connected to input of corrector, to output of which input of said power amplifier is connected.

EFFECT: higher precision.

3 cl, 8 dwg

FIELD: conversion of optical radiation by using nanotechnology.

SUBSTANCE: transparent nano-particles having volume of 10-15 cm3 are illuminated by white light. Nano-particles are activated by impurity atom with concentration of 1020-1021cm-3 and are strengthened in form of monolayer onto transparent substrate. Nano-particles are made of glass and are glued to substrate by means of optically transparent glue. Substrate can be made flexible.

EFFECT: high brightness of image.

4 cl, 1 dwg

FIELD: optical instrument engineering.

SUBSTANCE: modulator has non-monochromatic radiation source, polarizer, first crystal, first analyzer, and second crystal, second analyzer which units are connected together in series by optical coupling. Modulator also has control electric field generator connected with second crystal. Optical axes of first and second crystals are perpendicular to direction of radiation and are parallel to each other. Axes of transmission of polarizer and analyzers are parallel to each other and are disposed at angle of 45o to optical axes of crystals.

EFFECT: widened spectral range.

3 dwg

FIELD: engineering of displays.

SUBSTANCE: to decrease number of external outputs of screen in liquid-crystalline display, containing two dielectric plates with transparent current-guiding electrodes applied on them, each electrode of one plate is connected to selected electrode of another plate by electric-conductive contact, while each pair of electrodes is let out onto controlling contact zone, and electrodes, forming image elements of information field of screen, on each plate are positioned at angle φ similar relatively to external sides of plates, while angle φ satisfies following condition: 10°≤φ≤85°.

EFFECT: decreased constructive requirements for display.

4 cl, 4 dwg, 1 tbl

FIELD: optical engineering.

SUBSTANCE: device has optically connected single-frequency continuous effect laser, photometric wedge, electro-optical polarization light modulator, first inclined semi-transparent reflector, second inclined semi-transparent reflector and heterodyne photo-receiving device, and also second inclined reflector in optical branch of heterodyne channel, high-frequency generator, connected electrically to electro-optical polarization modulator, direct current source, connected to electrodes of two-electrode vessel with anisotropic substance, and spectrum analyzer, connected to output of heterodyne photo-receiving device.

EFFECT: possible detection of "red shift" resonance effect of electromagnetic waves in anisotropic environments.

1 dwg

FIELD: electro-optical engineering.

SUBSTANCE: fiber-optic sensor system can be used in physical value fiber-optic converters providing interference reading out of measured signal. Fiber-optic sensor system has optical radiation laser detector, interferometer sensor, fiber-optic splitter, photodetector and electric signal amplifier. Interferometer sensor is equipped with sensitive membrane. Fiber-optic splitter is made of single-mode optical fibers. Connection between fiber-optic splitter and interferometer sensor is based upon the following calculation: l=0,125λn±0,075λ, where l is distance from edge of optical fiber of second input of fiber-optic splitter to light-reflecting surface of sensor's membrane (mcm); λ is optical radiation wavelength, mcm; n is odd number within [1001-3001] interval.

EFFECT: simplified design; compactness; widened sensitivity frequency range.

4 cl, 1 tbl, 3 dwg

FIELD: electro-optics.

SUBSTANCE: method can be used in optical filter constructions intended for processing of optical radiation under conditions of slow or single-time changes in processed signal, which changes are caused by non-controlled influence of environment. Optical signal is applied to entrance face of photo-refractive crystal where phase diffraction grating is formed by means of use of photo-refractive effect. Reflecting-type phase diffraction grating is formed. For the purpose the optical signal with duration to exceed characteristic time of phase diffraction grating formation, is applied close to normal line through entrance face of photo-refractive crystal of (100) or (111) cut onto its output face which is formed at angle of 10°to entrance face. Part of entrance signal, reflected by phase diffraction grating, is used as output signal. To apply optical signal to entrance face of photo-refractive crystal, it has to be transformed into quazi-flat wave which wave is later linearly polarized.

EFFECT: power independence of processing of optical signal.

2 cl, 2 dwg

FIELD: measuring equipment.

SUBSTANCE: optical heat transformer includes base of body with optical unit positioned therein, transformer of heat flow and consumer of heat flow in form of thermal carrier. Optical unit consists of optical heat source and reflectors of coherent heat flows and concentrator - generator of coherent heat flow in form of two collecting mirrors and a lens, positioned on different sides of source, with possible redirection of coherent heat flow for interaction with transformer of heat flow with following transfer of heat flow.

EFFECT: decreased energy costs.

1 dwg

FIELD: measuring technique.

SUBSTANCE: electro chromic device has first substrate, which has at least one polymer surface, ground primer coat onto polymer surface, first electro-conducting transparent coating onto ground primer coat. Ground primer coat engages first electro-conducting coating with polymer surface of first substrate. Device also has second substrate disposed at some distance from first substrate to form chamber between them. It has as well the second electro-conducting transparent coating onto surface of second substrate applied in such a way that first coating is disposed in opposition to second one. At least one of two substrates has to be transparent. Device also has electrochromic medium disposed in chamber, being capable of having reduced coefficient of light transmission after electric energy is applied to conducting coatings. Electrochromic medium and ground primer coat are compatible.

EFFECT: simplified process of manufacture; cracking resistance.

44 cl, 1 dwg

FIELD: laser and fiber optics.

SUBSTANCE: in accordance to invention, optical wave guide is heated up during recording of Bragg grating up to temperature, which depends on material of optical wave guide, and which is selected to be at least 100°C, but not more than temperature of softening of optical wave guide material, and selected temperature is maintained during time required for recording the Bragg grating.

EFFECT: increased thermal stability of recorded Bragg gratings.

2 cl, 3 dwg

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