TWI317041B - Flat panel apparatus - Google Patents

Description

(1) 1317041 IX. Description of the invention [Description of the relevant application] The present invention is related to the following U.S. Patent Application Serial No. 09/368,921 filed on August 6, 1999; Japanese Application No. 09/406977; Application No. 09/4 07619, filed on September 28, 1999; Application No. 09/407620, filed on September 28, 1999; 09/490776

No.; all of the above applications are hereby incorporated by reference. In addition, the present application is related to U.S. Patent Nos. 5,661,351, 5, 867, 236, and 5, 903, 328, each of which is incorporated herein by reference. These applications for review and the patents issued have been filed by the applicants for this case. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a backlight assembly for a flat panel display, and more particularly to a single array of illuminators that produce high-density collimated light in two directions, which is suitable for large back-to-back tiles. Flat panel display using a prior art flat panel display manufactured according to a known active matrix (eg, TFT, etc.) liquid crystal display technology (eg, AMLCD) is generally mounted in front of a backlight module, the backlight module including fluorescent An array of illuminators. The diagonal size of this type of AMLCD flat panel display is increased by 1 to 2 inches per year, and the size of the desktop computer used during the 1999 period is about 15 inches (2) Ί317041

Diagonal viewing area. A few very large displays are made in a diagonal of 20 to 28 inches. The flat-panel display of the tiled AM LCD can be made in a 40-inch diagonal size, as described in U.S. Patent Application Serial No. 09/3 6 8 92 1 and 〇9/49〇77 6 of the review. As described in U.S. Patent No. 5,661,351, tiled flat panel displays require a highly collimated, highly collimated light backlight, a masked optical component, and a pixel aperture with very low luminous efficiency. Therefore, it is required to emit light of a high intensity range different from the usual 50,000 to 150,000 nit. Also, it is very important for the large area intensity uniformity of the tiled flat panel display. Achieving this intensity within a reasonable power consumption range requires a unique backlight design that includes temperature control features. Maintaining the brightness (i.e., high intensity) and uniform luminosity of the display over the entire active area of the display is very difficult to achieve. The intensity required for some applications, particularly the large-area, tiled, seamless flat-panel LCD display, allows the illuminator to produce a high amount of heat. In addition, although fluorescent illuminators are designed to operate at maximum efficiency at elevated temperatures, and are intended to operate at or near ideally designed temperatures, the ideal temperature is typically about 50 to 60 degrees Celsius. For example, a small edge-lit backlight module used on a notebook computer or a laptop-type portable personal computer does not generate a sufficient amount of light on a large-area display, and it cannot uniformly emit light over a large area. Therefore, it is necessary to illuminate the larger areas with a large array of fluorescent illuminators. Illuminator The number of illuminators needs to be in accordance with the size of the area required for illumination and the brightness requirements of the display. Large area displays typically require -5- (3) *1317041 multiple illuminators for proper illumination. Larger area displays (i.e., back-to-back displays) can be viewed from both sides in proportion to requiring more illuminators, as a single design feature is temperature controlled by the illuminator to achieve the desired density and to maintain illuminator efficiency optimization.

Since most displays are designed for widths greater than height, it is beneficial to place the illuminators horizontally in terms of durability and power considerations. Because fewer illuminator cathodes are present, fewer illuminators can be used and lower power losses. Preferably, the tubes are placed in a horizontal direction, stacked one above the other at predetermined predetermined intervals, and spaced apart from each other by a back-to-back display, one on each side of the array of illuminators. It is therefore a primary object of the present invention to provide a backlight module for illuminating a back-to-back display. Another object of the present invention is to provide a backlight module for a stand-alone or tiled large flat panel display. Another object of the present invention is to provide a backlight module designed to provide high intensity light output. Another object of the present invention is to provide a backlight module capable of transmitting highly collimated light. An additional object of the present invention is to provide a backlight module having very high operational efficiency. Another object of the present invention is to provide a backlight module having a cooling structure to maintain a substantially uniform lotus temperature. Another object of the present invention is to provide a backlight module that utilizes a horizontally mounted array of fluorescent tubes. -6 - 1317041 货 丨 κ κ 修正 替换 替换 替换 替换 修正 修正 修正 修正 修正 修正 修正 另一 修正 另一 另一 另一 另一 另一 另一 另一 另一 另一 。 。 。 。 。 。 。 。 。 。 。 Another object of the present invention is to provide a combined diffuser, collimator, and backlight unit for enhanced brightness film (BEF). Another object of the present invention is to provide a backlight assembly suitable for illuminating a large back-to-back tiled flat panel display having a gap that is invisible to the naked eye.

SUMMARY OF THE INVENTION In accordance with the present invention, a backlight module is provided that uniformly distributes visibility to a back-to-back planar liquid crystal display (LCD). Fluorescent illuminators are often used because of their high efficiency. However, the luminosity, efficiency, and illuminator life of the fluorescent illuminator are all coefficients of the lamp temperature. The present invention thus provides an apparatus and method for achieving uniformity of illumination and high degree of light collimation in a back-to-back display having a single backlight module source. In particular, the backlight module geometry can be optimized and the additional optical components can be used to achieve a stable and uniform illumination output of the backlight module through appropriate illuminator selection. A better balance of illuminators, illuminator spacing 'diffusers, and collimating optics is chosen to produce a high-resolution backlight module that has a very high and uniform intensity output over a very large surface area. Because light is reflected from each optical stack of the display, light is circulated from one display module to another. The optical stacking of the two display modules conventionally includes a polarizer, a reticle, a diffuser, and the like. In addition, light reflected from the light collimating optical component, the light enhancing film, and the diffusing film is also present in the optical stack. -7- (5) 1317041

The present invention provides a method of achieving the above objectives via a combination of components and appropriate design geometry. A particular application of the backlight module of the present invention is for the integration of two large tiled flat-panel displays having seams that are invisible to the naked eye, as described in the aforementioned U.S. Patent Application Serial No. 08/6 5,203, No. 09/3 6 8 29 1 'and as described in U.S. Patent No. 5,903,32. The present backlight module system has a thermal enhancement device (for example, as disclosed in U.S. Patent Application Serial No. 09/406,977), and the disclosure of which is incorporated herein by reference. The display is effective and reliable for large area high intensity light sources. In addition, the optimized geometry is used to minimize the illumination gradient between the two displays while maximizing the light output with the most efficient efficiency, which is also used to enhance the brightness film (BEF) and The light cycle maximizes the light output. Finally, the precise collimators required in the tiled flat-panel liquid crystal display, such as those disclosed in U.S. Patent Application Serial Nos. Nos. 09/024481 and 60/1 77447, are incorporated herein by reference. Define light outside the cutoff angle. It is apparent that although the backlight assembly of the present invention is preferably used for a tiled AMLCD flat panel display, it can also be used for stand-alone and similar stand-alone displays. [Embodiment] Overall, the present invention is characterized in that it is suitable for back-to-back flat -8 - (6) (6)

The 1317041 surface display device and method for controlling the degree of illumination, illuminance, and light collimation of a large area backlight. The backlight assembly is suitable for large tiling displays with high illuminance and precision with a predetermined degree of collimation. In addition, the present invention provides an optimized design for integrating back-to-back plane visualization with a single source of light, taking into account efficiency, cooling, luminosity, and quality. This design can be used for tiled flats as well as large monolithic or monolithic liquid crystal displays. Referring first to Figure 1, there is shown a pattern 100 of light transmission, i.e., luminosity, and efficiency (i.e., efficacy) of a conventional fluorescent lamp, all of which are a function of temperature. Fluorescent illuminators typically operate at maximum efficiency at a predetermined optimized lamp temperature. The maximum luminosity typically occurs at a point 102 near maximum. The ideal temperature To 104 can be determined from the temperature axis of the graph 100. The degree of regulation 104 is determined by the illuminator structure, particularly in accordance with the parameters of the phosphor and cathode structure mercury vapor pressure. The most efficient illuminator 128 is the level of the hot cathode type fluorescent illuminator. The hot cathode illuminator has a preheating period during heating and is therefore more susceptible to burning (i.e., igniting the gas in the illuminator. Referring now to Figure 2a, a side view 126 of a back-to-back flat panel display and its backlight assembly 14 is shown. The backlight assembly 1 24 light box chamber 1 26, fluorescent illuminator array 128, and light diffuser] illuminator 128 is cooled by a fan (not shown). Some display applications require additional optical components 132 to enhance Some characteristics of light. For example, a tiled flat-panel liquid crystal display needs to evenly display the image surface of the flat display (both wall efficiency and general cathode) at 122 including 30 ° emission height -9 - (7) ( 7)

Collimated light of 1317041. The additional backlight assembly 1 3 2 required for collimating light can be inefficient. Because of this, high illumination is required to be produced by backlight assembly 124. Referring now to Figure 2b, which shows a front view of the backlight assembly of Figure 2a, illuminator 128 is supported in chamber 1 26 by illuminator support 1 34. The illuminator 1 2 8 is wired to the ballast by the strap 1 138. The ballast 136 supplies a high frequency (typically 20-300 Hz) AC heater 1 28 . An efficient high frequency electrical device and any suitable unit known to those skilled in the art can be selected for use in the present invention, which is not limited to being part of the present invention. It is apparent that temperature sensing fan speed control circuits, illuminator dimming controllers, heat sinks, temperature control devices and methods well known to those skilled in the art can be combined with the backlight of the present invention to assist in controlling lighting. The surface temperature of the device 128. For example, illumination 134 may be the temperature of a heat sink measuring illuminator with an additional thermal resistor (not shown), and for adjusting one or more fans to adjust the speed of the fan, or for rectifying dimming stability. 136 voltage. Referring now to Figure 3, there is shown a schematic diagram 140 of a portion of a backlight assembly having a particular size and/or distance. Two illuminators 1 2 8 having 1 42 have a distance S 1 44 from each other. The illuminator 128 is located at a distance from the diffuser 130 having a size Η 146 which is designed in a manner well known to those skilled in the art. If the illuminator 128 needs to present a linear light source, the luminosity must be calculated according to the equation: the light box cavity 136 that can lower the 124, the source to the photo stabilizer ballast device, and the device, the device bracket, the voltage, the output of which is Diameter D is separated by a phase. According to the following -10- (8)•1317041

D d = tan'1

T H +

D

T Assuming that the required luminosity A is known, the number of illuminators can be easily calculated.

Refer to Figure 4' for a chart! 60, which shows the effect of the changes s 144 and Η 146 on the light output by the backlight assembly. Based on this information, the number of illuminators 128 of a predetermined size (diameter) D 142 that produce the necessary illuminance can be calculated.

The overall light output curve of backlight chamber 126 is a function of the number of illuminators 1 6 8 installed. The desired level of light level 1 6 2 is also displayed. It must be noted that as the number of lamp pitches increases, the light output also increases until the maximum illuminance capacity point 166 is reached, producing a maximum illuminance 164. Similarly, the more illuminators 168 are used, or the closer the illuminators are spaced apart, the illuminators will block each other's luminosity. It is also shown that the number of illuminators 1 6 8 corresponds to the desired light output 162. It must also be noted that although the diffuser 130 has high efficiency, it does not have a high transfer rate. The diffuser 1 30 acts as a diffuser on the side of the illuminator 128, but the same diffuser 1 30 serves as a reflector for the opposite display, for efficiency, collimating films I82 and 184 (BEF) Recycling light is required and the diffuser 130 must actuate both the transmitted and reflected light. This case found that the transmission rate of 50-75% is efficient. Now refer to Figure 7, which tracks several rays to explain in the diffuser -11 - (9) 1317041

130 and the interaction between the collimating films 182 and 184. The efficiency of such collimating films 182, 184 depends on a good optical coupling with their reflective surface 'considering a ray that radiates from illuminator 128 and directs to the upper diffuser 1 3 0 on point A, if diffuser 1 30 has a transmission of, for example, 60%, then 60% of the light will be transmitted via the diffuser 130 and cause a "Lambertian" light distribution aimed at the collimating film 182 (i.e., the distribution is uniform) Regarding all angles on the surface of the diffuser 130), however 40% of the light is reflected towards the lower diffuser 130 (also distributed in Lambertian form), and the light transmitted from point A is directed towards the collimating film. Point B, the angle of incidence of the ray (e.g., less than 60 degrees from the normal) causes the ray to be reflected back toward point C on the diffuser. At point C, 40% of the light is reflected back toward the collimating film 182, which is more efficient than re-entering the light in the illuminator chamber. Light entering the light chamber must span two diffuser/air interfaces (thus losing light) and some may be absorbed or diffused by the illuminator. Now consider another light that reflects from point c and directs to point D, which has a suitable angle of incidence (eg, 60 to 85 degrees) and is passed to the next collimating film 184 (Fig. 5), which is finally passed to the LCD. Form IN (Figure 5). Some of the light reflected from point C is transmitted to the lower diffuser 130 at point E. Some of this light will end up in the lower display, and some will reflect from the lower diffuser 1 30 and pass to point F 'other The light is transmitted to the point G' on the collimating film 182 and transmitted to the upper display. It can be seen that the light will continue to be reflected between the elements 1 30 and 182. -12-1317041. The efficiency coupling coupling improves the forward gain of the collimated light output. The key to the collimation rate is high. Efficiency, but a diffuser with relatively low transmission

Regardless of collimation and associated light recycling, a better approximation of the overall light output of the backlight assembly can be obtained by considering geometry. The illuminator tube 1 2 8 produces a uniform light that is substantially more than 3 60 degrees, the light is transmitted toward the first display, absorbed by the adjacent illuminator or injected backwards to impinge on another display 'the light reflected from a display is not Exiting through the illuminator array is either entering the second display' or absorbing into the array of fluorescent illuminators. The light absorbed by the adjacent illuminator can be represented by the angle of the light exiting the illuminator: φ χ = sin'1 The space S is given by the number N of illuminators of the device on the width W of the backlight chamber and is represented by the following formula: _W -ND ~ N-\ The light radiating to the front is given by its angle: Φforward =180-2^, the light that is emitted backward is the same as the light that is emitted to the front, so from -13- (11) (11)

.1317041 The total light emitted by the backlight assembly is: L - 360 + Lu * 〇 < * 1 where 1 is the total light output of a luminaire. The result is shown in Figure 4. Because the power consumed by each illuminator 128 is fixed, the efficiency is related to the number of luminaires and the light output. Curve 1 7 0 Straight line until the number of illuminators approaches 1 / 2 times the maximum ,, which refers to the maximum number of illuminators that can be installed in the assigned space. It is to choose the light output design point close to the turning point. Therefore, the optimal number of illuminations is not shown in Figure 4. Referring now to Figure 5, a cross-sectional view of a back-to-back backlight assembly of the present invention is shown. Shows many optical components that typically use a single back configuration. The light collimating optical assembly 132 is comprised of a phase-doped BEF 182 and a collimator 186. The diffuser and optical assembly 132 is sandwiched by 188 and 190. Plates 188 and 190 may be optically transmissive and, if expanded, must be sufficiently rigid to support the film member. The flat panel display 122 sits in front of the optical assembly 192, spaced apart by a distance F, leaving a spatial space 194 that is given to the internal air outlet to further cool the display 122. As previously stated, the BEF collimating optics is used to receive light at an angle of incidence, and for cycling, at approximately vertical angles, so is approximately the maximum desired 168 display and back to 184 with a glass plate Ming, and the optical group and with the 194 series high into the incident back -14- (12) (12)

'1317041 backlight assembly. What is desired for BEF is that it is possible to have a reflective area as much as possible, but the more illuminators produce the more light output, the first pass selection of the interval S is a small increase, and the illuminator spacing is added to make the illuminator The number is close to 10%' to provide satisfactory results. The action of coupling light into the BEF 182 is also affected by the distance B, which is the distance between the 182 and the 1200. The illuminance output of the BEF increases as the closer to the illuminator increases the light uniformity as it approaches the illuminator, and a reasonable 146 is required between the illuminator 1 28 and the glass optical support to act as the cooling chamber 126. Air circulation (as in Figure 2a, the preferred diffuser 130 is high efficiency, the low transmission diffuser is close to the Lambertian distributor to link the maximum amount of light to the BEF 182, and the backlight cavity 126 is recirculated The amount is the largest. Diffuse must be efficient to reflect light, it must have high transmission efficiency, must produce the Lambertian distribution of light. In addition, the illuminator can not have the rate, so in the illuminator spacing, back plane space and BEF pairs The fine-tuning must be considered in the design parameters of the spacing. In the above-mentioned U.S. Patent No. 5,903,328, 186 is described in detail in the open hexagonal cell comprising a honeycomb configuration, which is coated with a high coating. Cut-off angles or better use of sharp-type flat-panel flat-panel displays, non-tiling large single-chip or single-chip displays have the largest, and the proportion is reduced And 1 84 of 1 8 4 and the photo, but the purpose, in the space Η). , its choice and 184 device 130 must and its must be 100% absorbed by the illuminator collimator light absorption collimation angle cutoff collimation cutoff angle -15- (13) .1317041 does not need to be like a tile display A sharper, more efficient collimator design application is disclosed in U.S. Provisional Patent Application Serial No. 60,177,447. Unfortunately, a collimator with a physical structure creates a shadow image that is visible on the display to prevent imaging of the collimator. The display is placed at a predetermined distance F such that the cell image is overlapped or defocused. So it won't be seen by viewers on the viewer.

Figure 6 depicts the degree of collimation or the angular distribution of the light radiated from each optical sister. As described above, the diffuser 丨3〇 exhibits a Lambertian distribution of 200 radiation, and the BEFs 182 and 184 focus the light toward the front of the distribution 2〇2. For the type used herein, the distribution 202 has a theoretical forward gain. 2.2, the actual forward gain is approximately 1.9'. The BEF distribution 202 has significant optical energy remaining after the cutoff angle (approximately 301 in the preferred embodiment) for a seamless tiled plane The use of the display is not required. The collimator 186 is shown on the radiation profile 204 by cutting off light outside the collimation angle to eliminate unwanted light. The surface absorbance of the collimator cells must be sufficient to prevent more than 1% of vertical acuity illumination outside of the collimation angle. The design of the present invention achieves a brightness level that far exceeds the capabilities of existing industries, and the present invention can achieve luminosities exceeding 100,000 nits (candles per square meter). The luminosity output can exceed the uniformity of 50,000 nits by 10% luminosity as a reasonable design standard with excellent efficiency, which is superior to existing commercially available backlight units' even if it achieves a lower level of brightness.

-16- '1317041 • (14) Since it is possible, for example, to modify the optical configuration to achieve particularly suitable operational specifications and requirements, it will be apparent to those skilled in the art that the present invention is not limited to the disclosure. The examples are chosen for consideration, and are intended to cover all modifications and variations, and variations and modifications may be made without departing from the spirit and scope of the invention. Following the discussion of the present invention, the subject matter of the appended claims is hereby incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS A full understanding of the present invention will be obtained by reference to the appended claims. Where: Figure 1 is a graph of the luminosity versus temperature of a conventional fluorescent illuminator; Figure 2a is a cross-sectional view of a multi-illuminator backlight synchronous illuminating back-to-back display; Figure 2b is a plurality of illuminations shown in Figure 2a Figure 3 is a plan view showing the relationship between the illuminator and the diffuser; Figure 4 is a graph showing the light output as a function of the number of installed illuminators; Figure 5 is used in accordance with the present invention. A cross-sectional view of the backlight assembly of the back-to-back flat panel display; Figure 6 shows the luminosity as a function of the deviation from the vertical, which is caused by optical collimation; -17- (15) 1317041 Figure 7 A graphical representation of the typical reflection of light between a diffuser and a light collimating (i.e., enhanced brightness) film. For the sake of clarity and conciseness, similar components and components in the drawings will use the same reference numerals and numbers. [Main component symbol description] 1 0 0 : graphics

1 0 2 : point of maximum efficacy 104 : ideal temperature 1 2 0 : side view 122 : back to back flat display 124 : backlight assembly 126 : light box chamber 128 : fluorescent illuminator array 1 3 0 : light diffuser 1 3 2: Optical component 134: illuminator support frame support 1 3 8 : wiring tape 136: ballast 1 4 0 : 图解 diagram

1 4 2 : Diameter D

144: Distance S 146 : Height Η 1 60 : Chart -18- (16) .1317041 1 62 : Light level 166 : Maximum illuminator capacity point 168 : Illuminator 164 : Maximum illuminance 1 7 0 : Curve

1 8 0 : Backlight assembly outline section 1 82, 184: Collimating film 1 86 : Collimator 1 8 8 , 1 9 0 : Glass plate 1 9 2 : Optical component 1 9 4 : Space interval 200 : Lambert Distribution 202: Distribution 2 04: Radiation distribution curve

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Claims (1)

1317041 X. Patent application scope 丨 丨 丨 丨 日 日 日 日 , , , , , , , , , 第 第 第 第 第 第 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95 95 a first and a second flat panel display; a backlight module disposed between the first and the second flat display; the backlight module includes: a) a first enhanced brightness film having an incident side and an output side 'the output side of the first enhanced brightness film toward the first display side; b) a first diffuser having an incident side and An output side, the output side of the first diffuser is incident on the incident side of the first enhanced brightness film; c) a second enhanced brightness film having an incident side and an output side, the second enhanced brightness film The output side faces the second display side; d) a second diffuser having an incident side and an output side, the output side of the second diffuser being toward the incident side of the second enhanced brightness film; The incident side of the first diffuser, at least partially, transmits light to the first planar display via the first enhanced brightness film, and at least partially reflects light transmitted from the output side of the first diffuser Returning the first enhanced brightness film; and wherein the incident side of the second diffuser transmits, at least partially, light to the second planar display via the second enhanced brightness film, and at least partially transmits from the second Diffuser Light reflected back to the output side of the second brightness enhancement film. The flat device of claim 1, wherein the output side of the first enhanced brightness film reflects light at least partially toward the first diffuser. 3. The planar device of claim 2, further comprising: a first enhanced brightness film facing the first enhanced brightness film, the first enhanced brightness films being substantially vertically disposed with each other. 4- A planar device according to claim 1, wherein the incident side of the first φ diffuser produces a substantial Lambertian distribution. 5. The planar device of claim 1, wherein the output side of the second enhanced brightness film reflects light at least partially toward the second diffuser. 6. The planar device of claim 5, further comprising another second enhanced brightness film facing the second enhanced brightness film, the second enhanced brightness films being substantially vertically disposed with each other. 7. The planar device of claim 1, wherein the incident side of the second φ diffuser produces a substantial Lambertian distribution. 8. A planar device comprising: a first flat display and a second flat display; a light output portion disposed between the first and second flat displays; a first enhanced brightness film configured Between the first flat display and the light output portion; a first diffuser disposed between the first enhanced brightness film and the light output portion; -2-1317041 a second enhanced brightness film, Arranged between the second flat display and the light output portion; and a second diffuser disposed between the second enhanced brightness film and the light output portion. 9. The planar device of claim 8 wherein the output side of the first enhanced brightness film reflects, at least in part, light toward the first diffuser. 10. The planar device of claim 9, further comprising another first enhanced brightness film facing the first enhanced brightness film, the first enhanced brightness films being substantially vertically disposed with each other. 11. The planar device of claim 8 wherein the incident side of the first diffuser produces a substantial Lambertian distribution. 12. The planar device of claim 8, wherein the output side of the second enhanced brightness film reflects at least partially light toward the second diffuser. 13. The planar device of claim 12, further comprising another second enhanced brightness film facing the second enhanced brightness film, the second enhanced brightness films being substantially vertically disposed with each other. 14. The planar device of claim 8 wherein the incident side of the second diffuser produces a substantial Lambertian distribution. 15. A planar device comprising: a first flat panel display and a second flat panel display; a light output portion disposed between the first and second flat display; and a film of -3-*1317041, Arranged between the second planar display and the light output; and the film transmits a portion of the light from the light output to the second planar display and a portion of the light from the light output Reflected to. The first flat panel display. 16. The planar device of claim 15 wherein the film transmits light from the light output portion to the φ second planar display in the range of 50% to 75%.