RU2248025C2 - Light diode projector and method for presenting information on display - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: device has reflector, means for producing image and optical system for projecting image on display, as light source a board with light diodes is used, light flows of which are concentrated on an optical system. Protector is provided with sensor of outer light level and connected to common current adjuster.

EFFECT: broader range of use, higher precision, lower energy consumption.

2 cl, 16 dwg

Description

The claimed invention relates to optical-electronic devices intended for displaying color information on a surface (screen) in the form of symbols or images, and may find application in various devices displaying information as a display or television.

Known projector designed for color images, which contains two groups of light sources, a reflector, a color filter, a system for changing the image on the screen. Information on the screen is illuminated by direct light from one group of light sources and by rays passing through a color filter from another group of sources. Change of color and change of information is done mechanically. See, for example, US patent N 4057129, IPC G 09 F 13/12, NKI 40-563 "Display device having a special color effect (Display apparatus having means for creating a spectral color effect)", publ. 01/10/78.

The known device has disadvantages associated with the need to manually change the information field of the screen, which complicates the work with the device. In the known device, the number of acceptable color shades is limited by the capabilities of the color filter. In addition, a special drive is needed to change the color filters, which reduces its reliability.

Closer in technical essence and adopted for the prototype is the projector described in the patent of the Russian Federation N 2113066 "Video display system", IPC H 04 N 5/74, G 02 B 17/06, publ. 06/10/98.

A well-known picture tube contains a light source, a reflector, an optical system, a collimator, a light guide, a color liquid crystal matrix, means for acquiring an image on the matrix, and an optical system for projecting an image on a screen.

A disadvantage of the known color projector is that it has a high manufacturing complexity, high overall dimensions and weight, determined by the need to remove heat from the light source, low reliability and difficulties in adjusting the color gamut of the image during operation. In addition, failure of the light source may lead to the ignition of the device.

The aim of this invention is to reduce the complexity of manufacturing, reducing the cost of the product, its overall dimensions and weight, providing better color reproduction of the image, gaining the ability to adjust the color of the image and improving reliability and safety during operation. In addition, the proposed display has reduced power consumption, expanded the range of applications and increased the life of the device.

This goal is achieved by the fact that in a projector containing a light source, an optical system including a reflector, a collimator, a light guide, a color liquid crystal matrix, means for acquiring an image on the matrix and a screen for projecting an image, according to the proposal, the light source is a board with LEDs, arranged so that the light flux from them is concentrated on the optical system.

In a variant of the technical solution, the board with LEDs is made in the form of a paraboloid.

In an embodiment of the technical solution, the board is made in the form of a narrow strip curved in the shape of a parabola.

In a variant of the technical solution, the light source with LEDs is located in a solid transparent plastic case that fills the space between the board and the optical system.

In a variant of the technical solution, the board is a plane and is located on the side opposite to the reflector.

In the embodiment of the technical solution, the LEDs consist of three groups of red, green and blue colors, each group has a current regulator.

In an embodiment of the technical solution, the display is equipped with an ambient light sensor connected to a common current regulator included in the power supply circuit of the LEDs.

In an embodiment of the technical solution, the ambient light sensor is connected to a common controller and regulators included in the power supply circuit of the LED groups through a microprocessor.

In an embodiment of the technical solution, the information on the screen is projected by transmitting the light flux through a color liquid crystal matrix, and the light flux is formed by summing the three light fluxes from LEDs having three emission colors - red, green, blue, each of the light fluxes is regulated by a current regulator by signals from the ambient light sensor.

In an embodiment of the technical solution, the spectral composition of the radiation and the amount of light flux vary depending on the readings of the ambient light sensor.

In the embodiment of the technical solution, the LEDs of each group are located in their own separate unit that makes up the common housing.

Using the LED board as a light source provides a small overall picture tube size, low heat, thereby reducing the weight and overall dimensions of the apparatus. In addition, due to the high life of the LEDs (reaching 100 thousand hours), the reliability of the system increases. The entire light source, which is a board, can be performed on the principles of a printed circuit, which leads to a reduction in the complexity of manufacturing the apparatus. In addition, the projector provides a high degree of safety, since failure of LEDs does not cause any dangerous effects. The advantage of the LED light source is that it consists of several groups connected in series-parallel circuit, which makes it easy to switch depending on the voltage of the power source.

The implementation of the board with LEDs in the form of a paraboloid eliminates the need for special selection of lighting devices according to their parameters, which simplifies the manufacturing technology.

The implementation of the board in the form of a narrow strip, curved in the shape of a parabola, makes it possible to reduce the overall dimensions of the light source.

The location of the light sources in a solid transparent plastic case, filling the space between the board and the optical system, provides greater strength and moisture resistance of the tube.

The implementation of the LED board in the form of a plane located on the side opposite the reflector will allow you to create light sources with increased light flux.

The selection of LEDs from three groups of red, green and blue colors, in which each group has a current regulator, makes it possible to adjust the color of the total light flux, which is necessary when changing the ambient light according to the signals of the ambient light sensor.

The use of a microprocessor associated with an ambient light sensor allows you to adjust the color and amount of light flux depending on the ambient light when displaying information on a translucent screen so as not to blind the observer and, at the same time, ensure the best perception of information.

The use of separate blocks for each group of LEDs with a specific emission spectrum simplifies the installation of the illuminator and the individual adjustment of optical systems.

The invention is illustrated by 16 figures.

Figure 1 shows the structural diagram of the projector with LEDs located on the board in the form of a narrow strip, curved in the shape of a parabola.

Figure 2 is a section view aa along the arrow of the arrangement of the LEDs on the board.

Figure 3 shows a light source from LEDs, made in the form of a continuous structure of plastic.

Figure 4 presents a structural diagram of a device with LEDs located on the surface opposite to the reflector.

Figure 5 shows a variant of the projector with an external screen.

Figure 6 shows a diagram of the connection of LEDs with various emission spectra with current regulators.

Figure 7 shows the dependence of the light intensity of the LED radiation on the magnitude of the current flowing through it.

On Fig given the location of the light sensor of the external illumination of the screen.

Figure 9 shows a schematic diagram of the regulation of the luminous flux of LEDs using a light sensor.

Figure 10 has a graph of the change in luminous flux emitted by the screen, depending on the external illumination.

Figure 11 shows a graph of the change in the spectral composition of the light flux emitted by the screen, depending on the external illumination.

12 shows the location of the ambient light sensor when projecting an image onto a translucent screen.

On Fig presents a variant of the image transfer directly to the glass of glasses or protective glass of the helmet.

On Fig given a circuit diagram of the current control for LEDs with different emission spectra.

On Fig there is a graph of the luminous flux Φ of the LEDs depending on the external illumination E of the translucent screen.

On Fig shows a structural diagram of the location of the LEDs in various blocks.

Elements common to all figures are denoted identically.

LED projector is made as follows. The light sources 1 (Fig. 1) of the LEDs are arranged in a row on the board 2, which is a narrow strip made of plastic, for example, Plexiglas, and curved along a parabola so as to concentrate the light flux from the LEDs on the diffusing plate 3, after which it hits the collimator 4. These elements are located in the housing 5. The light guide 6 leads the light flux to the scattering lens 7, which evenly distributes the light flux to the color liquid crystal matrix 8. The latter has the means for obtaining images I (not shown in FIG.). After that, the light flux hits the screen 9. The screen 9 may have a separate housing 10.

The cross-sectional view A-A in the direction of the arrow (Fig. 2) gives an idea of the board 2 with the light diodes 1.

If it is necessary to ensure large luminous fluxes, the LEDs are also located on a three-dimensional surface having the shape of, for example, a paraboloid, and the surface itself is additionally coated on the outside with a reflective layer directing the light flux towards the plate 3 and collimator 4.

In an embodiment of the technical solution, the LEDs 1 together with the board 2 are located in a continuous transparent housing 11 (Fig. 3), the flat part of which is a kind of sector. The convex side 12 of the housing 11 with LEDs 1 has the appearance of a parabola, and the narrow side 13 is truncated and directed towards the optical system, consisting of a plate 3, a collimator 4 and an optical lens 7. As a material of the case, transparent plastic, for example polycarbonate, can be used. The outer surface of the housing 11 is covered with a reflective layer facing the inside of the housing.

In an embodiment of the technical solution, the light devices 1 are located on a flat board 14 (Fig. 4) on the surface opposite to the spherical reflector 15. An optical system is located in the focus of the reflector, for example, consisting of a scattering plate 3 and a scattering lens 16. The optical system is located in the center boards 14. The luminous flux from the lens 16 enters the color liquid crystal matrix 8. The luminous flux, after passing through the matrix, enters the screen 9 located in the housing 5.

In a variant of the technical solution, the image after the color liquid crystal matrix 8 is supplied to an external screen 17 (Fig. 5).

In the embodiment of the technical solution, the LEDs are divided into three groups with emission spectra - red (1 ′), green (1 ’’) and blue (1 ’’ ’) (Fig.6). In the power supply circuit of LEDs of various colors, there are current regulators, respectively for red 18, for green - 19, and for blue - 20. Transistors can be used as regulators. The total number of diodes depends on the above design options and the required maximum luminous flux. Their color ratio is determined by the need to obtain the total white standard light. LEDs are connected in series-parallel circuit. In each individual circuit, 4 series-connected LEDs of a certain emission spectrum. However, if necessary, the LEDs can be switched in a series-parallel circuit, where only 2 devices are connected in series or all the LEDs can be connected in parallel. The circuit may include a switch for changing the circuit of their inclusion. This allows you to adapt the device to various power sources. The arrangement of LEDs with a different emission spectrum on the board is determined by the convenience of installation. The circuit has a common voltage regulator 20.

When changing the magnitude of the current flowing through the LED, its luminous flux changes. With increasing current I, the luminous intensity I _Ф emitted by the LED increases almost rectilinearly (22), as shown in Fig. 7, where the current I is indicated on the abscissa axis and the luminous intensity I _Ф in relative units is indicated on the ordinate axis.

The light sensor 23 (Fig. 8) is positioned so that it does not get light from the screen of the raster display, and can be installed, as shown in Fig. 5, on the upper surface of the housing 5 or on the side (23 ’) on the surface of the screen. In this case, the sensor is equipped with a protective visor 24, blocking the luminous flux coming from the screen 9.

Electrically, the sensor 23 is connected to a common current regulator 20 (6, 9), which is in the common circuit of three parallel-connected groups of LEDs 1 ’, 1’ ’, 1’ ’’ with a different color of radiation.

The luminous flux Φ (25, Fig. 10) emitted by the screen 9 changes in direct proportion to the external illumination E. At external illumination above a certain threshold, for example, 500 lux, the luminous flux is 1 in relative units. This dependence can be nonlinear and is determined experimentally. Any kind of this characteristic is carried out due to the appropriate selection of the parameters of the controller 21.

The spectral composition of the total luminous flux Φ is determined by the ratio of the three luminous fluxes Φ _i emanating from LEDs with a different color of radiation. Their possible changes depending on the external illumination have letter indices (Fig. 11), which are distributed as follows: for the red spectrum - R (26), for the green - G (27) and for blue - B (28).

When projecting an image on a translucent screen, for example, on an airplane lamp or a car windshield 29, the ambient light sensor 23 (Fig. 12) is installed so that it does not interfere with the view, for example, next to the projection plane 29, onto which information is displayed after matrix 8 and lenses 7. The screen on the windshield or the lamp of the aircraft is a surface covered with a translucent mirror layer 30. The screen is positioned so that it allows the observer 31 to obtain the required information without being distracted from the appearance.

The screen may be one of the glasses of the glasses or the protective glass of the helmet 32 (Fig.13) having a translucent coating 30. The image is projected similarly to Fig.12. The luminous flux to the matrix 8 is fed through the light guide 6.

The ambient light sensor 23 is electrically connected through a microprocessor 33 to a common controller 21 and regulators 18, 19 and 20 (Fig. 14). The latter are electrically connected to the corresponding circuits with LEDs with different colors of radiation. So, the regulator 18 is in the circuit of the LEDs with a red spectrum of radiation, 19 is in the green, and 20 is in the power circuit of the LEDs with the blue spectrum.

Depending on the external illumination, the spectral composition of the information placed on the transparent screen also changes, as shown in Fig. 15, where there is a logarithmic scale along the abscissa axis for external illumination E, lux, and in ordinate, the components of the radiation flux F in relative units. The curves for each component have the same notation as in FIG. 10.

LEDs with different emission spectra, respectively, 1 ’, 1’ ’, 1’ ’’ ’can be located in separate blocks 34, 35, 36 (Fig. 16). Each block is equipped with a collecting lens, respectively 37, 38 and 39. The light fluxes emanating from the lenses are concentrated on the plate 3. The blocks are mounted in a common housing 40. This option is preferred when single superbright LEDs are used as light sources. The space between the LEDs and lenses can be flooded with transparent plastic. The electrical connection diagram of the elements of the system is similar to Fig.6 and 14.

LED projector operates as follows. The light flux from the LEDs 1 (Figs. 1, 3) located on the board 2, bent in the form of, for example, a paraboloid or parabola, is concentrated on the scattering plate 3, on which mixing and uniform distribution of light fluxes coming from the LEDs having different emission spectrum. Next, the mixed and evenly distributed light flux enters the collimator 4 and through the fiber 6 enters the scattering lens 7. Passing through the liquid crystal matrix 8, it enters the screen 9. The screen 9 can be located in a separate housing 10. A color image is formed on the matrix 8 behind image funds account.

Since the light flux from the LEDs is concentrated in a small solid angle, a reflector may not be required, and the board 2 itself can be made of inexpensive plastic. The design of the board, made in the form of a strip with light sources, the thermal emission of which is small, can significantly reduce the overall dimensions of the tube.

In the presence of a continuous plastic housing 11 (figure 3), the loss of absorption and scattering of the light flux is reduced.

In an embodiment of the technical solution, the light flux from the LEDs 1 located on the flat board 14 (FIG. 4), reflected from the parabolic reflector 15, is concentrated on the plate 3 and then goes to the scattering lens 16. After passing through the color liquid crystal matrix 8, the light flux with information , available on the matrix 8, gets on the screen 9. This option is used to obtain large light fluxes, where a large number of LEDs are required.

The present technical solution provides for projecting an image onto an external screen 17, as shown in FIG. Such an external screen can serve as a ceiling, wall, etc.

In the embodiment of the technical solution, the LEDs are divided into three color groups, red - 1 ', green - 1' 'and blue - 1' '' (Fig.6), and each group has current regulators 18, 19 and 20, with which you can change the current value of a separate group and thereby change the luminous flux (Fig.7) of one of the color components.

As you know, the resulting color emitted by the source can be formed by mixing three colors. By changing the luminous flux of one of the components, red - R (26), green - G (27) and blue - B (28) (11), you can change the total color of the radiation. In this case, it becomes possible to more easily and finely adjust the color of the image.

To improve visual adaptation, the luminous flux coming from the screen, it is desirable to adjust depending on external lighting.

So, in the dark, the brightness of the screen should be lowered, but in sunlight it should be increased, which is important for adapting vision. In order to adjust the brightness of the screen depending on the external emitter, the LED tube is equipped with an external light sensor 23 (Fig. 8). The sensor 23 (Fig. 8, 9) acts on the current regulator 21, which changes the total luminous flux (Fig. 8) emitted by the LEDs of all three light groups 1 ', 1' ', 1' '' at the same time, thereby providing a change screen brightness in accordance with an exemplary graph 25, Fig.10.

The sensation of color depends on the conditions of visual adaptation. For example, the luminous flux of an incandescent lamp at night causes a white sensation. The same luminous flux is perceived as yellow during the day. The light of a fluorescent lamp is perceived as white during the day and as bluish at night. (Gutorov M.M., Fundamentals of Lighting Engineering and Light Sources. - M.: Energoatomizdat, p.118). This fact emphasizes that the color gamut of the image should also change depending on the external backlight. The nature of these changes is not precisely established and requires experimental studies. However, the need for color correction on the screen depending on the external backlight is obvious. This technical solution allows this to be done by changing the color components of the light. An approximate dependence of the change in color gamut is shown in Fig.11. Under normal ambient illumination ranging from 150-1000 lux, the total luminous flux emitted by three groups of LEDs 1 ', 1' ', 1' '' corresponds to standard white (IOC), folding in the proportions red / green / blue - R / G / B = 1/4, 6/0, 06 (see Gutorov M.M., pp. 122-124), and varies according to Fig. 11 (curves 26, 27, 28) with changing external lighting. In the future, it is also possible to regulate color with external illumination with different color coloration.

The LED ratio in FIG. 6 does not correspond to this proportion. In particular, the number of blue LEDs is greater than that required to produce standard white light. The circuit is selected so that there is a certain symmetry, i.e. each circuit has 4 LEDs connected in series. The exact proportion is respected by the current regulators 18, 19 and 20 and by selecting the appropriate lighting devices.

To control the radiation of the screen depending on the external illumination, the circuit according to FIG. 9 can be applied. The characteristic of the controller 21 may have non-linear dependencies.

The problem of changing the color of information under external additional lighting is especially relevant in the case when the information is projected on a translucent screen. This is the case, in particular, when displaying an image on the windshield of a car or the lamp of an airplane. An external source of light - the sun or often changing street lighting, as well as possible complete darkness make it necessary to adjust both the brightness and the color of the image so that the information does not become dazzled in low light and is noticeable in full darkness and bright light. So, in bright sunlight, the color of information, so that it is noticeable, it is desirable to make, for example, red-orange, and in complete darkness, for example, slightly bluish. The ambient light sensor 23 (Fig, 13) is installed so that it does not interfere with the external view of the operator 31.

The sensor 23 acts on the current regulators 21, 18, 19 and 20, having non-linear dependencies, through a microprocessor system 33 (Fig. 15). Changes in the proportions of the color components, 26, 27, 28, providing the total color gamut, are carried out on the basis of a program embedded in the microprocessor, which, acting on the regulators 18-21, provides the required total light flux and the spectral composition of the light emitted by the LEDs. At the same time, the spectral composition and the luminous flux change in accordance with the best perception of the image. By changing the settings of the controls 18, 19 and 20, it is possible to provide an individual adjustment of the brightness and color of the image depending on the ambient light.

A variant of the technical solution in which the LEDs differing in the distribution spectrum of the luminous flux 1 ', 1' ', 1' '' are distributed in different blocks 34, 35 and 36 (Fig. 16) allows for finer adjustment of the light distribution and is preferable for cases when single superbright LEDs are used as light sources. It also simplifies the installation of the projector's lighting system.

Thus, the proposed technical solution provides correction of image brightness and automatic color adjustment as the parameters of external illumination change.

The technical and economic advantages of the proposed light tube are as follows:

1. Reduced the complexity of manufacturing and weight of the product.

2. The cost of the product is reduced by reducing the complexity.

3. The range of possible applications of the product has been expanded.

4. Improved capabilities for more accurate color reproduction of the image.

5. Increased moisture resistance and explosion safety of the product due to the complete tightness of the demonstration device and reduce thermal load on the system.

6. Improved the ability to perceive information in the presence of external lighting.

7. Reduced light loss and increased device life.

8. Reduced power consumption.

Claims (8)

1. An LED projector comprising a light source, an optical system, a color liquid crystal matrix, means for acquiring an image on the matrix and a screen for projecting an image, characterized in that the light source is a board with LEDs arranged so that the light fluxes from them are concentrated on an optical system in which a scattering lens is provided for distributing the light flux onto a color liquid crystal matrix, the LEDs being divided into three groups with spectra and radiation - red, green, blue, and each group has a current regulator, and the screen is provided with an ambient light sensor associated with a common current controller included in the LED power circuit. 2. The LED projector according to claim 1, characterized in that the board with LEDs is made in the form of a paraboloid. 3. The LED projector according to claim 1, characterized in that the board is made in the form of a narrow strip curved in the shape of a parabola. 4. The LED projector according to claim 1 or 3, characterized in that the light source with LEDs is located in a solid transparent plastic case. 5. LED projector according to any one of claims 1, 2, characterized in that the ambient light sensor is connected to a common controller and regulators included in the power supply circuit of the LED groups through a microprocessor. 6. LED projector according to any one of paragraphs.1, 2, characterized in that the group of LEDs with a specific emission spectrum are located in a separate unit included in a common housing. 7. A method of presenting information on a screen, which consists in projecting information by transmitting a light flux through a color liquid crystal matrix, characterized in that the light flux is formed by summing three light fluxes from LEDs having three radiation colors - red, green, blue, while each of the light fluxes is regulated by signals from an ambient light sensor, the light source is a board with LEDs arranged so that the light flux from them is concentrated It is mounted on an optical system in which a scattering lens is provided for distributing the light flux to a color liquid crystal matrix, and the screen is equipped with an ambient light sensor connected to a common current controller. 8. The method according to claim 7, characterized in that the spectral composition of the radiation and the magnitude of the light flux varies depending on the readings of the ambient light sensor.

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