CN209784698U - Narrow-frame side-entering type liquid crystal display laser backlight source - Google Patents
Narrow-frame side-entering type liquid crystal display laser backlight source Download PDFInfo
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- CN209784698U CN209784698U CN201920455275.2U CN201920455275U CN209784698U CN 209784698 U CN209784698 U CN 209784698U CN 201920455275 U CN201920455275 U CN 201920455275U CN 209784698 U CN209784698 U CN 209784698U
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Abstract
The utility model discloses a narrow-frame side-entering type liquid crystal display laser backlight source, which comprises a visible light laser group, a light beam shaping device, a reflecting device and a liquid crystal display light guide plate; after laser beams emitted by the visible light laser are reflected by the reflecting device, the light propagation direction is changed by 180 degrees and then the laser beams enter the light guide plate of the liquid crystal display through the light transmitting surface; each visible light laser beam emitted by the adjacent visible light laser groups generates light overlapping which is larger than 10% of the area of each light spot when the visible light laser beam enters the light-transmitting surface on the side surface of the light guide plate of the liquid crystal display through a reflecting device, and the sum of the lengths of the laser beam spots of the visible light laser groups in the same waveband on the light-transmitting surface on the side surface of the light guide plate of the liquid crystal display is larger than or equal to 0.65 time of the length of the light-transmitting surface. The utility model discloses can realize obtaining the effect of best LCD screen brightness and picture luminance color homogeneity with the least visible laser of quantity.
Description
Technical Field
The utility model relates to a laser LCD's light source, concretely relates to side income formula laser LCD's backlight structure.
background
The optical system of the existing liquid crystal display is designed for the surface light source using LED as the light emitting basic element, and is very mature.
The LED light source has the advantages that:
The spatial divergence of the light is about 150 DEG without axial difference, and the light energy is approximately uniform
The shape and size of the light emitting region of the LED can be changed by semiconductor processing
The white light synthesis method of the LED-based display light source is simple and can form uniform white light
the LED light source has low heat dissipation requirement, and the heat sink has small, light and thin volume and simple structure
Broad spectral width of the LED device, with negligible effect on color due to wavelength change with increasing temperature
the advantages determine that the LED can be made into a patch lamp bead type narrow-band surface light source consisting of a large number of light-emitting low-power light spots.
The single-point light emitted by the LED surface light source is uniform in energy distribution and low in light power, and the LED luminous points with large number can be arranged in the length direction to form the uniform surface light source with high total luminous intensity. The width of a light emitting area of an individual LED lamp bead of the surface light source can be made smaller than the width of a light inlet surface of the light guide plate, and the light coupling efficiency of the light guide plate is high; the thickness of 3mm is convenient for heat dissipation and installation, and the length can be freely cut, so the backlight module is widely used for the backlight source of the side-entry type liquid crystal display.
the side-in type liquid crystal display backlight is characterized in that a patch lamp bead type narrow-band surface light source formed by a large number of light emitting points with low power is arranged on the side face (long and thick or wide and thick) of a PMMA light guide plate, and low-brightness and uniform light emitted by each LED lamp bead is incident on the light guide plate and then is totally emitted. A plurality of scattering regions are arranged on one surface (length and width) of the light guide plate and are used for destroying the total reflection of light in the light guide plate, so that the surface light source is formed on the surface of the light guide plate (length and width) from which the light rays are emitted. For example, 176 white light LED beads with a light emitting area of 7 × 2mm are used on one side of a 70-inch lcd tv, each bead has 2 LED light emitting points, and 352 white light LED light emitting points are used to ensure that the LED white light enters the light guide plate to form a uniform lcd backlight source with a larger area.
The liquid crystal display using the LED as a light source can satisfy only the requirement of the liquid crystal display of 2K resolution. The color gamut coverage, color saturation, color reduction and color number required by the 4K and 8K liquid crystal displays are far from reaching the standard.
Laser display is a novel display technology, and a laser light source is the best display light source available to human beings and can meet the requirements of relevant standards of 4K and 8K displays. Compared with the traditional light sources of displays such as LED, OLED, quantum dot and cold cathode lamp, the laser light source has the following advantages: has the advantages of high color rendering, narrow spectral width, and minimal beam divergence, and thus, semiconductor laser light sources have been widely used as light sources for projection display devices.
However, the laser source is also faced with the following problems if it is used as a side-entry lcd light source:
1. The all-solid-state laser has large volume, low efficiency, extremely high cost and complex structure, and cannot be used as a light source for a flat-shaped liquid crystal display.
2. The existing laser light source which can be used as a liquid crystal display can only be a semiconductor laser.
3. Commercial visible light semiconductor lasers are all end-emitting lasers.
In addition to the absolute advantages of the end-emitting visible lasers over LEDs in terms of color, other applications have the following significant disadvantages:
The packaging volume is large (about 10 times of that of an LED with the same luminous power), the packaging structure is complex, and surface mount packaging cannot be realized;
The spacing between the light emitting points of the end-emitting visible light laser is more than 10 times larger than that of the LED due to the limitation of the packaging form, and the excessive light emitting gap can not form 'non-color difference white light' and 'surface light source with uniform brightness'
Low efficiency of the electro-optical conversion (about 50% -30% of an LED with the same luminous power);
The laser wavelength is sensitive to temperature change, the wavelength is easy to generate red shift along with the rise of temperature, and the heat dissipation requirement is several times higher than that of an LED;
Forced heat dissipation is needed for the end-emitting visible laser light source, otherwise, the long-time use of the end-emitting visible laser light source causes thermal attenuation of output power, and the service life is further influenced.
The power density of a light emitting region emitting visible light laser is tens of times of that of the LED;
The monochromaticity of laser light is good, and when the laser light is used as a light source of a display, white light synthesis must be performed using a three-primary-color laser light source.
Laser interference problem of speckle noise of picture
The light emitting area of the end-emitting visible light semiconductor laser is only 100um wide, the power density of the light emitting area is extremely high, and the plastic light guide plate is easily damaged
Most importantly, the divergence angle of the laser beam emitted by the end-emitting visible light semiconductor laser is anisotropic, the fast axis divergence angle is about 40 degrees, the slow axis divergence angle is less than 10 degrees, and the shape of the light spot is elliptical and cannot be changed by a semiconductor processing technology.
There are many patents related to the application of semiconductor laser light source emitting visible light at the end to liquid crystal display, and none of these patents is to install the laser at the side of the light guide plate following the existing manufacturing scheme of side-in type LED surface light source. For example, patent CN104344284A and patent CN104180244A disclose a "laser backlight device", in which red, green, and blue lasers are combined by a lens to form white light, and then the white light is incident on a light guide plate module, and the divergence angle of the combined white light is very small. After entering the light guide plate module, laser beams are expanded through the doped scattering particles in the light guide plate module, so that a laser surface light source with high brightness and uniform light distribution is formed. Patent CN104180244A discloses a "laser backlight source device", in which a light guide tube is arranged around the light guide plate, a light opening is left on the light guide tube, a scattering body is present inside the light guide tube, when a laser beam passes through the light guide tube, the scattering body inside the light guide tube performs diffuse reflection on the laser to generate a scattering white laser, and the scattering white laser enters the light guide plate to form a surface light source. In both schemes, scattered laser light scattered by nanoparticles is used as a backlight source of the display, and the scattered laser light forms 360-degree illumination light in the same space as that of a cold cathode lamp (fluorescent lamp). When the scattered light is used as a display backlight source, the scattered light is emitted in a space of 360 degrees, and 25-40% of loss is required to be generated, so that the light incidence rate (coupling rate) of the final light guide plate is about 60-75%. For a cold cathode lamp (fluorescent lamp) with low price, low power consumption and less heat generation, the low light incidence rate of the light guide plate is not a problem; however, for the laser with high price, high power consumption and large heat generation, the light loss of 25-40% generated when light is guided in the incident light is unacceptable, because the excessive light incident loss of the light guide plate means that the display uses more lasers, and thus the cost and the power consumption of the laser liquid crystal display are greatly increased. What is more, the solution causes the frame width of the liquid crystal display to be too large, which results in the appearance of the whole liquid crystal display being not beautiful and the light source structure being incompatible with the mechanical mounting structure of the liquid crystal screen and other devices. Most importantly, this solution only solves the white light synthesis problem, but does not solve the shimming problem, which causes the brightness of the display to be unevenly distributed.
Patent 201520476596.2 discloses a surface light source structure for laser display, in which a plurality of rgb lasers are arranged on four sides of a light guide plate. Because the three-color laser directly enters the light guide plate, the intensity distribution of the laser with the interval of over-far red, green and blue three-color laser is uneven, and the white light cannot be synthesized to cause the situation of screen blooming phenomenon and uneven screen brightness (figure 1), so that the normal use requirement of liquid crystal display cannot be met. However, for a large-sized liquid crystal display screen, higher brightness is required to support the picture quality, and the practical technical implementation according to the patent scheme requires more than 600 lasers to meet the backlight requirement of the large-sized liquid crystal display screen, so that the cost and the heating power consumption of the laser liquid crystal display screen are multiplied.
The existing patent schemes can not solve the practical problems of picture color spots, color bands, uneven light and shade distribution of a light field and low brightness caused by mismatching of a visible light end emission semiconductor laser and an optical system of the existing side-entering LED liquid crystal display.
The existing side-in type LED liquid crystal display backlight optical system cannot be matched with an end-emitting laser source.
If the end-emitting semiconductor laser source is used for the side-in type liquid crystal display, and the commercialization is realized, a novel side-in type liquid crystal display backlight source structure suitable for the optical parameters and the structure of the visible light end-emitting semiconductor laser must be developed.
SUMMERY OF THE UTILITY MODEL
In view of this, the utility model provides a narrow frame side income formula LCD laser backlight, this backlight can eliminate the color spot, color lump, light and shade stripe and the colour temperature inequality that different wave band visible light laser beams do not have the overlap and lead to in the LCD light guide plate to obtain the even light field that distributes.
A narrow-frame side-entering type liquid crystal display laser backlight comprises an end-emitting visible light laser group, a light beam shaping device, a reflecting device and a liquid crystal display light guide plate;
The end-emitting visible light laser group is arranged on the back of the liquid crystal display shell, the front of the liquid crystal display shell is attached to the liquid crystal display light guide plate, the end-emitting visible light laser group has a certain optical path from the light-passing surface of the side surface of the liquid crystal display light guide plate, and laser beams emitted by the end-emitting visible light laser are reflected by the reflecting device, the light propagation direction of the laser beams is changed by 180 degrees, and then the laser beams enter the liquid crystal display light guide plate through the light-passing surface; each beam of visible light laser beam emitted by the adjacent end-emitting visible light laser groups generates light overlapping which is larger than 10% of the area of each light spot when the visible light laser beam enters the side light-transmitting surface of the light guide plate of the liquid crystal display through a reflecting device, and the sum of the lengths of the laser beam spots of the end-emitting visible light laser groups in the same waveband on the side light-transmitting surface of the light guide plate of the liquid crystal display is larger than or equal to 0.65 time of the length of the light-transmitting surface; a beam shaping device is arranged between the end-emitting visible light laser group and the reflecting device, between the reflecting device and the light-transmitting surface on the side surface of the light guide plate of the liquid crystal display; the beam shaping device adjusts the divergence angle of the visible light laser beam.
further, the end hairAn optical path L between the optical axis of the visible light laser group and the incident surface corresponding to the light guide plate of the liquid crystal display, and a divergence angle theta of the laser beam emitted by the visible light laser group emitted from the end in the length direction of the incident surface of the light guide plate of the liquid crystal displayyDetermining the projection length w, optical path L and divergence angle theta of laser beam on the side light-passing surface of the light guide plateyThe relation of the projected length w of the light beam is calculated by the formula (1)
Further, the end-emitting visible light laser group comprises at least one red light laser with the center wavelength of 600-700 nm, at least one green light laser with the center wavelength of 500-550 nm and at least one blue light laser with the center wavelength of 410-480 nm; the laser spots of the three lasers are mutually overlapped to form a white light laser source.
Further, the beam shaping device is one of a spherical mirror, an aspherical mirror, a reflecting prism, a beam expanding prism, a micro-optical lens device, a wave mirror, a cylindrical mirror, a fresnel lens, a diffuse reflection device, a fly-eye lens, a scattering device, an optical wedge, a grating, a cemented lens, a plane mirror or a curved mirror, or a combination of the above optical devices.
Further, the reflecting device is made of a material with a refractive index larger than 1, so that a solid structure visible light laser beam is subjected to a total reflection phenomenon in the reflecting device; when the reflecting device is a hollow cavity structure, a high-reflection material corresponding to the wavelength of the laser beam exists on the inner wall of the hollow cavity; when the reflector is a surface reflector, the combination of a solid structure and a hollow cavity structure is adopted.
Furthermore, a reflecting surface used for reflecting laser in the reflecting device is a plane, an aspheric surface, a spherical surface, a micro-optical structure surface, a diffuse reflecting surface or a grating surface; on the reflecting surface of the reflecting device, the laser light generates optical phenomena of specular reflection, diffuse reflection or 'refraction + reflection'.
Furthermore, micro-optical structures are arranged on light inlet and outlet surfaces on the light guide plate and the reflecting device of the liquid crystal display and used for correcting the divergence angle of the visible light laser beam.
Further, the light inlet and outlet surfaces of the light guide plate and the reflector of the liquid crystal display are provided with a spherical surface, an aspherical surface, a cylindrical surface or a prism for correcting the divergence angle of the laser beam.
Furthermore, a thin film optical device capable of eliminating Newton rings, realizing scattering, realizing refraction and realizing uniform light exists between the light entrance light transmission surface and the light exit light transmission surface of the light beam shaping device, the light guide plate of the liquid crystal display, the reflecting device and the optical device.
Further, the side-in laser liquid crystal display backlight source performs forced heat dissipation by using air cooling, water cooling or semiconductor refrigeration.
Further, the flat cable of the liquid crystal display and its related electronic components are wrapped or disposed outside the reflection device.
Has the advantages that:
1. the utility model discloses can make the polybase colour end in the backlight send the visible laser beam and carry out long distance propagation and then produce the large tracts of land overlap in LCD light guide plate side, eliminated among the prior art technical scheme that the different wave band visible laser beam does not have the color lump and the light and shade stripe that the overlap leads to in the LCD light guide plate to obtain the even LCD laser backlight area source of light field distribution.
2. The utility model discloses a reflection device carries out 180 turns to the laser beam, can be under the condition that does not increase LCD's side frame width/height dimension, ensures in the backlight every bunch of laser beam can produce sufficient light overlap in the LCD light guide plate of LCD light guide plate and realize that the narrow frame outward appearance of complete machine improves and account for the screen ratio.
3. The utility model discloses under the total light energy condition that satisfies LCD lighting needs, increase the facula length of end transmission visible light laser on LCD light guide plate incident surface, can increase the output energy who reaches end transmission visible light laser alone, reduce the use number of laser instrument, and do not reduce LCD's picture luminance degree of consistency, practice thrift manufacturing cost.
4. The utility model discloses can solve the fixed, too big and liquid crystal display that leads to of end transmission visible laser appearance "big chin" and fixed, heat radiation structure and LCD winding displacement and relevant electron device installation conflict problem.
5. The utility model discloses can solve the heat dissipation problem of end transmission visible light laser instrument comprehensively, promote laser LCD's life comprehensively.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention;
Fig. 2 is a schematic view of the present invention applied to a laser liquid crystal display;
FIG. 3 is a schematic view showing the divergence angles of laser beams in the length and width directions of the incident surface of the light guide plate of the LCD;
FIG. 4 is a schematic diagram showing the relationship between the spatial distance from the end-emitting visible light laser to the light-transmitting surface of the light guide plate of the LCD and the length of the light spot;
FIG. 5 is a schematic view of the area covered by the laser beam in the light guide plate of the LCD;
FIG. 6 is a schematic diagram showing the relationship between the length of the light spot of the semiconductor laser on the incident surface of the LCD light guide plate and the length of the LCD light guide plate;
FIGS. 7 and 8 are schematic diagrams of embodiments in which optical devices are selected for the beam shaping device;
FIG. 9 is a schematic diagram of an embodiment of an optical device for use as a reflector
Wherein, the 1-end emission visible light laser unit, the 101-blue light semiconductor laser unit, the 102-green light semiconductor laser unit, the 103-red light semiconductor laser unit, the 2-beam shaping device, the 201-aspheric surface laser collimation lens, the 202-beam expanding concave cylindrical lens, the 203-micro optical beam shaping device, the 204-waver, the 205-beam expanding micro optical lens, the 206-Baville prism, the 207-plano convex cylindrical lens, the 208-plano concave cylindrical lens, the 3-reflection device, the 301-blue light beam combining lens, the 302-green light beam combining lens, the 303-red light high reflection mirror, the 304-trapezoidal prism, the 4-liquid crystal display light guide plate, the 41-scattering area, the 5-liquid crystal display screen, the 6-light homogenizing/diffusing brightness enhancement film group, the 7-liquid crystal display shell, The 71-end emits visible light laser heat sink, and the arrow line is laser beam.
Detailed Description
The present invention will be described in detail below with reference to the accompanying drawings by way of examples.
As shown in fig. 1, the utility model provides a backlight source of side-entering laser liquid crystal display, the liquid crystal display light guide plate 4 is fixed on the inner side of the liquid crystal display shell 7, the end-emitting visible light laser set 1 is installed on the heat sink 71, the heat sink 71 is fixed on the back of the liquid crystal display light guide plate 4 (the side of the liquid crystal display light guide plate 4 with length multiplied by width and close to the liquid crystal display shell 7) on the outer side of the liquid crystal display shell 7; a space distance L exists between the end-emitting visible light laser group 1 and a side light-passing surface (a surface with the length multiplied by the thickness or the width multiplied by the thickness of the liquid crystal display light guide plate 4) of the liquid crystal display light guide plate 4, wherein the L is the shortest optical path from a laser beam emitted by the visible light end-emitting semiconductor laser to the side light-passing surface of the liquid crystal display light guide plate after passing through a necessary optical device; at least one reflecting device 3 is present in a position close to the side light-passing surface of the light guide plate 4 of the liquid crystal display; beam shaping devices 201 and 202 are arranged between a side light-passing surface of the light guide plate 4 of the liquid crystal display and a reflecting device 3 close to the side light-passing surface, wherein the beam shaping device 201 is used for expanding a laser beam theta y, and the beam shaping device 202 is used for expanding the laser beam theta x; laser beams emitted by the visible light laser end emitting semiconductor laser 1 pass through the beam shaping device 201 and then are reflected by the reflecting device 3 close to the side light-passing surface of the liquid crystal display light guide plate 4 to form the incident beam shaping device 202, and the laser beams expanded by the beam shaping devices 201 and 202 are incident to the liquid crystal display light guide plate 4 through the side light-passing surface of the liquid crystal display light guide plate 4; the expanded laser beam enters the light guide plate 4 of the liquid crystal display and then is diffused by the diffusion region 41 on the light guide plate 4 of the liquid crystal display to finally form a uniform surface light source.
as shown in fig. 2, two sets of end-emitting visible lasers 1 constitute the light source of a 24-inch liquid crystal display. 101-blue light semiconductor laser, 102-green light semiconductor laser, 103-red light semiconductor laser, 203-micro optical beam shaping device, 204-wave mirror, 3-PMMA trapezoidal reflector, 4-liquid crystal display light guide plate, 5-liquid crystal display screen, 6-dodging diffusion brightening film group,
One end-emitting visible light laser group 1 comprises a 101-blue light semiconductor laser with the central wavelength of 410-480 nm, a 102-green light semiconductor laser with the central wavelength of 500-550 nm and a 103-red light semiconductor laser with the central wavelength of 600-660 nm; the laser spots of the three lasers are mutually overlapped to form a white light laser source.
The two sets of end-emitting visible lasers 1 constitute the light source of a 24-inch liquid crystal display. In the end-emitting visible light laser group 1, the light emitting centers of the 01-blue light semiconductor laser, the 102-green light semiconductor laser and the 103-red light semiconductor laser are equidistant 15mm, and the light emitting centers of the three end-emitting visible light lasers are arranged on the same straight line and have the same optical path with the light passing surface on the side surface of the light guide plate of the liquid crystal display.
The optical path L of the end-emitting visible light laser group 1 from the light-passing surface of the side surface of the light guide plate of the liquid crystal display is 12 cm; laser beams emitted by lasers with various wavelengths in the end-emitting visible light laser group 1 are shaped by the 203-micro optical beam shaping devices corresponding to the lasers, and the distance between the 203-micro optical beam shaping devices and light outlets of the end-emitting visible light lasers 101, 102 and 103 is 1.5 mm. The visible light laser beam is converted from an initial divergence angle theta x of 5-10 degrees and theta y of 35-40 degrees into a beam with theta x 'of 0.2 degrees and theta y' of 80 degrees. The shaped laser beam enters a 3-PMMA 45-degree isosceles trapezoid reflecting device with the thickness, length, width and height of 530 multiplied by 16 multiplied by 3mm, and reaches a 204-wave mirror after being reflected twice by the 3-PMMA trapezoid reflecting device. The 204-wave mirror is arranged between the 4-liquid crystal display light guide plate and the 3-PMMA 45-degree isosceles trapezoid reflecting device and is tightly arranged with the 3-PMMA 45-degree isosceles trapezoid reflecting device and the side light passing surface of the 4-liquid crystal display light guide plate. 204-wave mirror expands the beam of the theta x' of the laser beam
θ x 'changes from 0.2 ° to 80 °, θ y' remains unchanged.
After the optical transmission and shaping processes, the projection length of the light spots of the end-emission visible light lasers 101, 102 and 103 on the light-passing surface of the side surface of the light guide plate of the 4-liquid crystal display is 201 mm.
The overlapping area of the light spots of the adjacent end visible light emitting lasers is 93% of the area of each light spot. The 24-inch 16:9 liquid crystal display light guide plate is 530mm long, 290mm wide and 2mm thick, and the sum of the projection lengths of light spots of the end-emitting visible light laser on the light passing surface on the side surface of the 4-liquid crystal display light guide plate is 75%.
As shown in FIG. 3, the spatial distance between the end-emitting visible light laser set 1 and the light guide plate 4 of the liquid crystal display and the divergence angle θ of the laser beam emitted from the end-emitting visible light laser set 1ythe optical length L is calculated by formula (1) in relation to the beam projection length w of the laser beam on the side light-passing surface of the light guide plate 4 of the LCD
A plurality of end-emitting visible light laser groups 1 spaced from the side light-passing surface of the LCD light guide plate 4, and having a light beam projection length w on the side light-passing surface of the LCD light guide plate 41,w2...,wn(n is a natural number not less than 1) sum of the sums wpW is not less than 65% (W is the length of the side light-passing surface of the light guide plate of the liquid crystal display), WpCalculated by the formula (3)
wp＝w1+w2+...+wn (2)
Divergence angle θ of laser beams emitted from each end-emitting visible light laser group 1xnAnd the beam projection width h of the laser beam in the thickness direction of the side light-passing surface of the light guide plate 4 of the liquid crystal displaynEmitting L of visible light laser group 1 from each endnDetermination of hnCalculated by equation (5)
The visible light end emitting semiconductor laser is arranged on the back of the liquid crystal display shell, and then the reflecting device is used for turning the light path of the laser beam to enter the light guide plate, so that the functions of the laser beam are as follows: firstly, the optical path L between the end-emitting visible light laser group 1 and the liquid crystal display light guide plate 4 is enlarged, so that the area (shown in figure 5) covered by a certain laser beam with a divergence angle emitted by the visible light end-emitting semiconductor laser in the liquid crystal display light guide plate 4 is enlarged, namely the space luminophor of the laser beam in the liquid crystal display light guide plate 4 is enlarged, thereby reducing the space optical energy density of the laser and further reducing/eliminating color blocks and bright and dark stripes caused by energy distribution difference of the laser on the liquid crystal display light guide plate 4 so as to obtain a liquid crystal display laser backlight area light source with uniform light field distribution; secondly, under the condition of meeting the total light energy requirement of the liquid crystal display, the light spot length of the visible light end emission semiconductor laser on the incident surface of the light guide plate is increased, the light spot overlapping area between adjacent visible light laser emitting lasers of different wave band ends can be increased, the larger the overlapping area of the laser light spots of different wave bands is, the smaller the color difference of the backlight source is, and the more uniform the color temperature is; thirdly, the output energy of the semiconductor laser emitted by the single visible light end can be increased, and the number of the lasers used can be reduced; the four-use of the turning light path can ensure that the width of a side frame of the liquid crystal display is not increased, the appearance of the whole liquid crystal display using the three-primary-color laser light source is not influenced, and the optimal optical path L is obtained under the condition.
as shown in FIG. 4, L1、L2And L3The optical paths from the end-emitting visible light laser set 1 to the side light-passing surface of the light guide plate 4 of the liquid crystal display are respectively. Laser beam y-axis divergence angle theta of end-emitting visible light laser group 1y，w1、w2，w3The projected length w of the laser beam on the side light-passing surface of the light guide plate 4 of the liquid crystal display is shown.
Taking a commercially available green light semiconductor laser and a commercially available 70-inch lateral-entry LED liquid crystal television light guide plate (1540mm multiplied by 873mm multiplied by 2mm) as an example, the typical value of the fast axis divergence angle of the green light semiconductor laser is 35 degrees, and the typical value of the slow axis divergence angle is 5 degrees; the area coverage of the side light-passing surface (1540mm × 2mm) of the backlight LED light bar light guide plate of the 70-inch LCD TV is actually measured to be 81%.
When the sum of the lengths of the laser beams emitted by the green light semiconductor laser and the light spots on the light passing surface of the side surface of the light guide plate needs to be larger than 1540mm multiplied by 0.8, L1＝2mm，L2＝12mm，L380mm, divergence angle thetayAt 35 °, it can be calculated according to equations (1) and (3):
w1＝1.26mm，w2＝7.56mm，w3＝50.47mm
Therefore, when the distance between the green light semiconductor laser and the side light-passing surface of the light guide plate is L1In time, 977.7 ends are needed to emit visible light laser group 1; when the distance between the green light semiconductor laser and the side light-passing surface of the light guide plate is L2When in use, 165 visible light ends are needed to emit the semiconductor lasers 1; when the distance between the green light semiconductor laser and the side light-passing surface of the light guide plate is L3In time, 24.41 ends are needed to emit the visible light laser group 1; while an LED requires 352 light emitting points.
The length of the green light semiconductor laser on the side of the light guide plate of the 70-inch liquid crystal display television is cumulatively calculated according to the minimum package appearance length of the semiconductor laser of 4mm, and the sum is about 4720 mm: 3908mm for a distance L1, 660mm for L2 and 96mm for L3; the total installation length of the laser emitting visible light from the three primary colors end needs: 11724mm for L1, 1980mm for L2 and 288mm for L3. If a uniform white light source is to be formed, the mounting length of L1 is far beyond the side length of the light guide plate of the lcd, L2 is far beyond the single side length of the light guide plate of the lcd, and only L3 is sufficient for the light source of the lcd.
According to the three groups of data, the farther the end-emitting visible light laser is away from the liquid crystal display, the lower the light power per unit area in the light guide plate is, the larger the overlapping area of the laser beams is, the more uniform the three primary colors are mixed, the better the chromatic aberration, color spots and color blocks are eliminated, and the better the white light synthesis effect is; the fewer the number of lasers used, the lower the cost; the laser is used in small quantity, which is convenient for the backlight source structure design of the liquid crystal display.
as shown in FIG. 6, w1and w2Is the beam projection length, w, of the end-emitting visible light laser set 1 on the incident surface of the liquid crystal display light guide platepIs the sum of the projected lengths of the beams. The x-axis is the thickness direction of the light guide plate of the liquid crystal display, the y-axis is the length direction of the light guide plate of the liquid crystal display, and the z-axis is the width direction of the light guide plate of the liquid crystal display.
As shown in fig. 7 and 8, the optical shaping device 2 employs an aspheric laser collimating lens 201, a Y-axis beam expanding concave cylindrical lens 202 and an X-axis beam expanding concave cylindrical lens 208. The reflecting device 3 is a mirror box having an aspherical mirror disposed therein.
As shown in fig. 9, the reflection device employs a blue light beam combiner 301, a green light beam combiner 302 and a red light high-reflection mirror 303; the laser beam emitted by the red light semiconductor laser 103 firstly passes through the aspheric laser collimating lens 201 to collimate the divergence angle of the fast axis and the slow axis of the laser beam, and the collimated red light laser beam irradiates the reflecting surface of the red light high reflecting mirror 303 and is plated with a 600-680 nm 45-degree high reflecting film) so that the propagation direction of the red light beam is turned by 90 degrees and then is emitted to the green light beam combining mirror 302. The green light beam combining mirror 302 (one surface of the green light beam combining mirror is plated with a 600-680 nm 45-degree high-transmittance film, and the other surface is plated with a 500-550 nm 45-degree high-reflection film and a 600-680 nm 45-degree high-transmittance film) is used for combining the red light and the green light. The green light semiconductor laser 102 emits a laser beam, the laser beam collimates the divergence angles of the fast axis and the slow axis of the laser beam through the laser beam collimation micro-optical lens, and the propagation direction of the green light beam irradiated on the green light beam combiner 302 is turned by 90 degrees. The combined red and green light beams are emitted to the blue beam combiner 301. The blue light beam combining mirror 301 (one surface of the blue light beam combining mirror is plated with a 400-480 nm 45-degree high-transmittance film, and the other surface is plated with a 600-680 nm 45-degree high-reflectance film, a 500-550 nm 45-degree high-reflectance film and a 400-480 nm 45-degree high-transmittance film) is used for combining white light of blue light, red light and green light. The blue laser beam emitted by the blue laser 101 is collimated by the aspheric laser collimating lens 201 to the divergence angle of the fast axis and the slow axis of the laser beam, and then emitted to the blue beam combiner 301. After passing through the blue light beam combining mirror 301, the red, green and blue lasers are combined into a white light beam. The divergence angle of the white light beam after being expanded by the Y-axis beam expanding micro-optical lens 206 is thetay，θx. Through a divergence angle of thetay，θxThe white light beam is reflected by the trapezoid prism, the propagation direction of the white light beam is changed by 180 degrees, then the white light beam enters the 202-axis beam expanding micro-optical lens, and the white light beam is expanded into a laser beam with theta y equal to 170 degrees and theta X equal to 120 degrees after passing through the X-axis beam expanding micro-optical lens 202.
The laser beam Y-axis beam expanding concave cylindrical lens 202 in this embodiment may be replaced by a dove prism, a wave mirror, a diffractive optical device, a grating, an aspherical mirror, and a spherical mirror. The laser beam X-axis beam expanding concave cylindrical lens 208 can be replaced by a diffraction optical device, a grating, an aspherical mirror, a spherical mirror, ground glass, a light-transmitting fiber bundle, light-transmitting material particles, a light-transmitting scattering film and other devices capable of forming an optical beam expanding function.
In summary, the above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A narrow-frame side-entering type liquid crystal display laser backlight source is characterized in that the backlight source comprises a visible light laser group, a light beam shaping device, a reflecting device and a liquid crystal display light guide plate;
The visible light laser group is arranged on the back of the liquid crystal display shell, the front of the liquid crystal display shell is attached to the liquid crystal display light guide plate, the visible light laser group has a certain optical path from the light transmitting surface on the side surface of the liquid crystal display light guide plate, and laser beams emitted by the visible light laser are reflected by the reflecting device, the light propagation direction of the laser beams is changed by 180 degrees, and then the laser beams are incident to the liquid crystal display light guide plate through the light transmitting surface; each visible light laser beam emitted by the adjacent visible light laser groups generates light overlapping which is larger than 10% of the area of each light spot when the visible light laser beam enters the light-transmitting surface on the side surface of the light guide plate of the liquid crystal display through a reflecting device, and the sum of the lengths of the laser beam spots of the visible light laser groups in the same waveband on the light-transmitting surface on the side surface of the light guide plate of the liquid crystal display is larger than or equal to 0.65 time of the length of the light-transmitting surface; a beam shaping device is arranged between the visible light laser group and the reflecting device, between the reflecting device and the light-passing surface on the side surface of the light guide plate of the liquid crystal display; the beam shaping device adjusts the divergence angle of the visible light laser beam.
2. The narrow-bezel side-entry lcd laser backlight according to claim 1, wherein an optical length L from an optical axis of the visible light laser group to a corresponding incident surface of the lcd light guide plate and a divergence angle θ of a laser beam emitted from the visible light laser group in a length direction of the incident surface of the lcd light guide plateyDetermining the projection length w, optical path L and divergence angle theta of laser beam on the side light-passing surface of the light guide plateyThe relation of the projected length w of the light beam is calculated by the formula (1)
3. the narrow-bezel side-entry liquid crystal display laser backlight of claim 2, wherein the set of visible lasers comprises at least one red laser having a center wavelength of 600-700 nm, at least one green laser having a center wavelength of 500-550 nm, and at least one blue laser having a center wavelength of 410-480 nm; the laser spots of the three lasers are mutually overlapped to form a white light laser source.
4. The narrow-bezel side-entry lcd laser backlight of claim 1, wherein the beam shaping device is one of a spherical mirror, an aspherical mirror, a reflective prism, a beam expanding prism, a micro-optical lens device, a wave mirror, a cylindrical mirror, a fresnel lens, a diffuse reflection device, a fly-eye lens, a scattering device, an optical wedge, a grating, a cemented lens, a flat mirror, or a curved mirror, or a combination thereof.
5. The narrow-bezel edge-lit lcd laser backlight of claim 4, wherein the reflective device is fabricated with a material having a refractive index greater than 1 to produce a total reflection of the solid structure visible laser beam within it; when the reflecting device is a hollow cavity structure, a high-reflection material corresponding to the wavelength of the laser beam exists on the inner wall of the hollow cavity; when the reflector is a surface reflector, the combination of a solid structure and a hollow cavity structure is adopted.
6. the narrow-bezel lateral-entry liquid crystal display laser backlight according to claim 5, wherein a reflective surface of the reflective device for reflecting laser light is a planar surface, an aspheric surface, a spherical surface, a micro-optical structured surface, a diffuse reflective surface, or a grating surface; on the reflecting surface of the reflecting device, the laser light generates optical phenomena of specular reflection, diffuse reflection or 'refraction + reflection'.
7. The narrow-bezel edge-lit lcd laser backlight of claim 6, wherein micro-optical structures are present on the light guide plate of the lcd and the light entrance and exit surfaces of the reflective device for modifying the divergence angle of the visible laser beam.
8. the narrow-bezel edge-lit lcd laser backlight of claim 7, wherein the light-guiding plate and the light-exiting surface of the reflector have spherical, aspherical, cylindrical or prismatic surfaces for modifying the divergence angle of the laser beam.
9. The narrow-bezel edge-lit lcd laser backlight of claim 8, wherein thin-film optical devices capable of eliminating newton's rings, achieving scattering, achieving refraction, and achieving uniformity of light are present between the light-in and light-out light-passing surfaces of the beam shaping device, the lcd light guide plate, the reflector device, and the optical device.
10. The narrow-bezel side-entry laser backlight for a liquid crystal display of claim 9, wherein the side-entry laser backlight for a liquid crystal display uses air cooling, water cooling, or semiconductor cooling for forced heat dissipation; the flat cable of the liquid crystal display screen and related electronic components are wrapped or arranged outside the reflecting device.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920455275.2U CN209784698U (en) | 2019-04-04 | 2019-04-04 | Narrow-frame side-entering type liquid crystal display laser backlight source |
| EP20781839.4A EP3951488A4 (en) | 2019-04-04 | 2020-03-27 | Laser backlight source of narrow-frame edge-lit liquid crystal display |
| PCT/CN2020/000056 WO2020199699A1 (en) | 2019-04-04 | 2020-03-27 | Laser backlight source of narrow-frame edge-lit liquid crystal display |
| US17/493,798 US11635561B2 (en) | 2019-04-04 | 2021-10-04 | Laser backlight for narrow-frame edge-lit type liquid crystal display |
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| CN201920455275.2U CN209784698U (en) | 2019-04-04 | 2019-04-04 | Narrow-frame side-entering type liquid crystal display laser backlight source |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109960081A (en) * | 2019-04-04 | 2019-07-02 | 许江珂 | A kind of narrow frame side entering type liquid crystal display laser backlight |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109960081A (en) * | 2019-04-04 | 2019-07-02 | 许江珂 | A kind of narrow frame side entering type liquid crystal display laser backlight |
| CN109960081B (en) * | 2019-04-04 | 2024-01-26 | 许江珂 | Narrow-frame side-entry type liquid crystal display laser backlight source |
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