JP3905894B2 - Video display device - Google Patents

Description

  The present invention relates to an image display device, and more particularly to an image display device that projects an image from the back of a screen.

  Currently, there are projector devices that project images from a personal computer or a television to a screen and display them on a large screen. As the projector apparatus, there is a rear projection type apparatus that projects an image from the back of the screen in addition to an apparatus that projects an image from the front of the screen.

  In a rear projection type projector apparatus, light generated from a light source is generally transmitted using an optical switching element such as a mirror. At this time, a change in the amount of transmitted light according to the video signal, that is, optical modulation is performed, so that a video according to the video signal is projected onto the screen.

Conventionally, there has been disclosed an image display device that realizes an increase in light modulation speed and a high contrast (see, for example, Patent Document 1).
The optical switching element used in this image display device is composed of a reflecting portion having a reflecting surface that reflects light from a light source, and a light transmissive member provided with an inhibiting portion that inhibits the progress of light near the focal point of the reflected light. Is done. An image display device is configured by arranging the optical switching elements in one dimension and further providing a scanning mechanism for scanning the reflected light.

  In the optical switching element described above, when the reflecting surface is a plane, the reflected light reaches the light-transmitting member as parallel rays and is transmitted except for the blocking portion. When the reflecting surface is bent by electrostatic force or the like, the amount of transmission decreases, and finally the reflected light is focused by the light transmitting member. In the vicinity of the focal point at this time, an obstructing portion is provided, and the transmission amount is suppressed to almost zero.

In such an optical switching element, an efficient operation is performed even with a very small bend, and the transmission amount at the OFF time is almost zero due to the inhibition part. Therefore, in an image display device that performs light modulation using this light switching element, high contrast is realized along with improvement in light modulation speed.
JP 2002-148530 A (paragraph number [0012], FIG. 6)

  However, the image display device described above requires a light source for projecting an image on a screen. Therefore, a space for arranging the light source inside the apparatus and a heat dissipation mechanism for suppressing heat generation from the light source that emits strong light are required, and the apparatus configuration is complicated.

Further, since light emitted radially from one light source is optically modulated, the image projected on the screen becomes darker from the center to the end, resulting in luminance unevenness.
The present invention has been made in view of these points, and an object thereof is to provide a video display device capable of reducing luminance unevenness as well as simplifying the device configuration.

In the present invention, in order to solve the above-described problem, in a video display device that projects an image from the back side of a screen, light emission that is disposed on the back side of the screen and has directivity and emits light according to the video signal. A light emitting unit in which elements are arranged in a one-dimensional direction, and scanning that is arranged on the back side of the screen and scans the light emitted from the light emitting unit in a direction orthogonal to the arrangement direction of the light emitting elements. The scanning unit includes reflection means for reflecting the light and projecting the light onto the screen, and the scanning unit includes a plate-like body that translates in the scanning direction of the light. The body is provided with a plurality of reflecting means each having a reflection angle determined according to the projection position of the light on the screen according to the scanning direction , and the light emitting unit is disposed between the screen and the scanning unit. Arrangement Is, emits the light to said reflecting means of said scanning unit, the light emitted is, the image display apparatus is provided, characterized in that projected on the rear surface of the screen is reflected by said reflecting means .

According to said structure, a light emission part is arrange | positioned between a screen and a scanning part, and the light which has the directivity emitted from the light emission part according to the video signal is with respect to the arrangement direction of a light emitting element by a scanning part. It is scanned in the orthogonal direction and projected onto the screen as an image. The light emitted from the light emitting element is reflected by a plurality of reflecting means provided on a plate-like body that moves parallel to the scanning direction of the light provided in the scanning unit, and is projected onto the screen. The plurality of reflecting means are provided on the plate-like body in accordance with the light scanning direction, with the reflection angle determined according to the projection position of the light on the screen.

According to the present invention, light emitting elements having directivity and emitting light corresponding to video signals are arranged in a one-dimensional direction to form a light emitting part, and light from the light emitting part is arranged in the arrangement direction of the light emitting elements. By scanning in a direction orthogonal to the light emitting element itself, the light emitting element itself becomes a light source that emits light according to the video signal, and the light from each light emitting element is projected onto the screen almost in parallel, simplifying the device configuration Is possible, and luminance unevenness can be reduced. Further, the light emitting unit is disposed between the screen and the scanning unit, and the light emitted from the light emitting element of the light emitting unit is provided on the plate-like body that moves parallel to the light scanning direction of the scanning unit in accordance with the light scanning direction. Since the light is reflected by a plurality of reflecting means having a reflection angle determined according to the projection position of light on the screen and projected onto the screen, the projection distance to the screen is shortened. And the depth of the apparatus can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a side view showing an outline of a video display apparatus according to a first embodiment of the present invention. Moreover, FIG. 2 is a figure which shows the structure of the LED unit used for this Embodiment, (A) is a front view, (B) is a top view.

  The video display apparatus according to the present embodiment includes a screen 100 for projecting video, and an LED unit 10 that is arranged behind the screen 100 and in which LEDs (Light Emitting Diodes) 1 are arranged in a one-dimensional direction. Yes.

  The LED 1 has directivity and functions as a light emitting element that emits light by itself. In this embodiment, a lens having a highly condensing lens is used to prevent light diffusion. Note that the LED 1 corresponds to one pixel on the screen 100 and is actually configured by LEDs corresponding to the three primary colors (RGB) of red, green, and blue.

  The LED 1 is driven by, for example, a dedicated driver IC, and emits light whose luminance is changed in accordance with video data indicating gradation and the like. The driver IC is provided, for example, on a driving circuit inside the LED unit 10 and turns on the LED 1 with a luminance corresponding to the input video data using, for example, a pulse.

  As shown in FIG. 2, the LED unit 10 includes LEDs 1 arranged in a row in the horizontal direction in this embodiment. In addition, the number of LED1 which comprises 1 unit can be arbitrarily determined according to the size of the screen 100, such as 32 pieces, for example.

  In such a video display device, light corresponding to video data for one line is emitted from the LED unit 10 for a predetermined period. Since this light has directivity, it is projected onto the screen 100 in the form of a light beam. At this time, the light emitted from each LED 1 is displayed on the screen 100 as spot-like pixels.

  In this way, by arranging the LEDs 1 in a one-dimensional direction, the light emitted from each LED 1 is projected onto the screen 100 in a substantially parallel state, so that the luminance unevenness within one line displayed on the screen 100 is sufficient. Can be reduced.

Next, scanning with respect to the LED unit 10 configured as described above will be described.
FIG. 3 is a side view for explaining scanning of the video display apparatus according to the present embodiment.
As shown in FIG. 3, the video display device according to the present embodiment rotates the LED unit 10 around a rotation axis parallel to the arrangement direction of the LEDs 1, so that the light emitted from the LED units 10 is arranged in the arrangement of the LEDs 1. Scan in a direction perpendicular to the direction.

  First, after the line 1 is displayed on the screen 100, the LED unit 10 rotates by a predetermined angle so that the light from the LED unit 10 is projected to the position of the line 2. Then, at the moment when the rotation is completed, light corresponding to the video data of the line 2 is emitted from the LED unit 10 and the line 2 is displayed on the screen 100. By repeating such an operation, each line is scanned in the vertical direction and projected onto the screen 100 as an image. In this embodiment, such scanning is performed by a scanning unit including a stepping motor. Details of the scanning unit will be described later.

4A and 4B are diagrams illustrating a screen configuration example of the video display device according to the present embodiment, in which FIG. 4A is a front view of the screen, and FIG. 4B is a side view illustrating how the LED unit is scanned.
As shown in FIG. 4, in the present embodiment, a screen having predetermined vertical and horizontal pixels on the screen 100 is configured by scanning the LED unit 10. The number of pixels constituting one screen can be arbitrarily determined according to the size of the screen 100, for example, 32 horizontal pixels × 16 vertical pixels. At this time, the LED unit 10 rotates stepwise according to each line displayed on the screen 100 and repeats it for each frame. For example, in the case of a 16-line screen, it is rotated in 16 steps according to each line.

Thus, by scanning the line in which the luminance unevenness is reduced as described above by the rotation of the LED unit 10, it is possible to obtain a good screen with little luminance unevenness.
Next, display control of the video display device configured as described above will be described.

FIG. 5 is a diagram illustrating a configuration example of a display control circuit of the video display apparatus according to the present embodiment.
As shown in FIG. 5, the display control circuit of the video display apparatus according to the present embodiment includes frame memories 111 and 112, a write address generator 113, a read address generator 114, a horizontal synchronization signal counter 115, and a selector 116. 117 and three-state buffers 118 and 119.

  The display control circuit configured as described above receives, for example, video data of 60 frames per second in synchronization with the data clock, together with the horizontal synchronization signal and the vertical synchronization signal. Note that the video data indicates a gradation, and has a bit width corresponding to a desired number of gradations.

Each of the frame memories 111 and 112 has a function of storing video data for one frame, and in the present embodiment, these read and write alternately.
The write address generator 113 and the read address generator 114 are configured by a counter or the like. These start or stop the counting operation in accordance with a predetermined timing determined by the horizontal synchronizing signal and the vertical synchronizing signal. During the count operation, a write address for writing video data to the frame memories 111 and 112 and a read address for reading video data written to the frame memories 111 and 112 are generated in synchronization with the data clock. .

The horizontal synchronizing signal counter 115 has a function of counting the horizontal synchronizing signal and alternately outputting high or low for each frame.
The selectors 116 and 117 select either the write address or the read address in accordance with the output from the horizontal synchronization signal counter 115. Then, the selected write address or read address is sent to the frame memories 111 and 112, respectively.

  The three-state buffers 118 and 119 switch between the through state and the high impedance state according to the output from the horizontal synchronization signal counter 115, and control the input of the video data to the frame memories 111 and 112.

  It is assumed that the output of the horizontal synchronization signal counter 115 becomes high at a certain frame in the above configuration. At this time, the frame memory 111 is in a read state and the frame memory 112 is in a write state. Accordingly, the read address is selected by the selector 116 and the write address is selected by the selector 117. Further, the 3-state buffer 118 is in a high impedance state, and the 3-state buffer 119 is in a through state. As a result, the input video data passes through the 3-state buffer 119 and is input to the frame memory 112.

  Then, the video data in the frame is written into the frame memory 112 according to the write address. At the same time, video data written in the frame memory 111 in the previous frame is read from the frame memory 111 according to the read address and transferred to the driver IC that drives the LED 1. In addition, a line address for designating line data among the read addresses is transferred to the scanning unit.

Thereafter, in the next frame, the horizontal synchronization signal counter 115 outputs low, and the reverse operation is performed.
Next, a transfer example of the line address and video data output from the circuit will be described.

FIG. 6 is a diagram illustrating an example of line address transfer.
As shown in FIG. 6, the line addresses transferred to the scanning unit are line addresses L1, L2 corresponding to the number of lines Ln displayed on the screen 100 during a frame signal indicating the start of a frame, that is, during one frame. ,. . . Ln is transferred. For example, if the number of display lines on the screen 100 is 16, the line address L1 corresponding to the line 1 to the line address L16 corresponding to the line 16 are transferred during one frame.

  In the scanning unit, the angle control of the LED unit 10 is performed so that the line address corresponds to the display line on the screen 100. For example, the line address L1 is controlled so that the angle of the LED unit 10 becomes an angle for displaying the line 1. Details of the angle control of the LED unit 10 according to the line address will be described later.

FIG. 7 is a diagram illustrating an example of video data transfer.
As shown in FIG. 7, the video data transferred to the LED unit 10 is video data P1 for the number of pixels Pn constituting one line for each phrase (one period obtained by dividing one frame according to the number of display lines). , P2,. . . , Pn are transferred to the driver IC. At this time, the RGB video data is transferred for each pixel. For example, if the number of pixels in one line is 32, video data P1 corresponding to the pixel 1 to video data P32 corresponding to the pixel 32 are transferred for each RGB during one phrase.

  A latch signal is transferred between phrases. With this latch signal, the transferred video data is latched in a register in the driver IC. For example, video data transferred in a certain phrase is latched in a register of the driver IC by a latch signal transferred between the next phrase. Thereafter, in the next phrase, the LED 1 is turned on in accordance with the video data latched as described above by the lighting control of the driver IC. At the same time, the video data in the phrase is transferred to the driver IC.

In this way, display control for projecting an image corresponding to the image data onto the screen 100 becomes possible.
Next, angle control of the LED unit 10 by the scanning unit 50 will be described.

FIG. 8 is a diagram for deriving an angle set in the LED unit.
As shown in FIG. 8, when the LED unit 10 is in a horizontal state, the distance from the central axis 10a of the LED unit 10 parallel to the arrangement direction of the LEDs 1 to the screen 100 is X. The distance between the lines on the screen 100 is Y0.

  In the present embodiment, it is assumed that the LED unit 10 is rotated around the central axis 10a. First, it is assumed that the LED unit 10 is rotated by θ1 around the central axis 10a in order to display the LED unit 10 on a line one distance above the line displayed in the horizontal state by a distance Y0. At this time, the relationship of tan θ1 = Y0 / X is established. Similarly, tan θn = (nY0) / X is established when θn rotation is performed to display on a line separated by a distance nY0 (n is an integer).

Therefore, the angle θn set in the LED unit 10 with respect to the line located at a distance nY0 from the line in the horizontal state is
θn = tan ⁻¹ (nY0) / X (1)
Given in. Note that the angle corresponding to the lower line from the horizontal state can also be derived in the same manner as described above, and is given by the following equation.

θn = tan ⁻¹ (−nY0) / X (2)
FIG. 9 is a graph showing the relationship between the position of each line displayed on the screen and the angle of the LED unit.

  This figure is a graph of the above formulas (1) and (2). Thus, the angle change of LED unit 10 becomes small, so that it is far from the line displayed when LED unit 10 is in a horizontal state.

Next, the control for setting the above angle to the LED unit 10 will be described.
FIG. 10 is a top view illustrating a configuration example of the scanning unit. FIG. 11 is a view taken in the direction of arrow A in FIG.

  As shown in FIG. 10, the scanning unit 50 includes a stepping motor 51, a driving disk 52, a positioning disk 53, a light emitting unit 54, a sensor light receiving unit 55 that senses light generated by the light emitting unit 54, and an arm 56. is doing.

  The stepping motor 51 has a function for rotating the LED unit 10 around a rotation axis parallel to the arrangement direction of the LEDs 1. As described above, in the present embodiment, the LED unit 10 is rotated around the central axis 10a.

Both the drive disk 52 and the positioning disk 53 have a common shaft with the stepping motor 51.
As shown in FIG. 11, an arm 56 connected on the same straight line as the light projection direction of the LED unit 10 is attached to the drive disk 52. When the driving disk 52 is rotated stepwise in the clockwise direction by driving the stepping motor 51, the rotation is transmitted by the arm 56, and the LED unit 10 is stepped in the counterclockwise direction around the central axis 10a. Rotate to.

The positioning disk 53 is provided with a window through which light generated by the light emitting unit 54 is transmitted.
FIG. 12 is a diagram showing details of the positioning disk and the window provided thereon, (A) is a front view, (B) is a diagram showing details of the window developed on a straight line, and (C). It is a figure which shows an example of the pulse produced | generated based on the light which passed the window.

  As shown in FIG. 12A, in the present embodiment, windows having different functions are provided on the outer peripheral side and the inner peripheral side of the positioning disk 53, respectively. The outer peripheral side window functions as a rotation / stationary control window for the stepping motor 51. The inner peripheral window functions as a positioning window for designating the rotational position of the stepping motor 51. Of the light generated by the light emitting unit 54, the light transmitted through the window is detected by the sensor light receiving unit 55, and the detected light is pulsed.

  FIG. 12B shows a state in which each window provided in the positioning disk 53 is developed on a straight line. In this example, 16 lines of positioning windows and rotation / control windows are shown. ing.

  The positioning window is provided on the moving radius of the positioning disk 53 that gives a rotation angle corresponding to each line when the stepping motor 51 is rotated. On each of the above-mentioned moving radii, a positioning window is provided as a set in order to generate a line address of the corresponding line. With this configuration, the rotational position of the stepping motor 51 can be designated.

For example, when a positioning window corresponding to 16 lines is provided as shown in the figure, a 4-bit code representing the line address of the corresponding line is generated by the positioning window provided on each moving radius of the positioning disk 53. The For example, a positioning window corresponding to each digit of 2 ⁰ , 2 ¹ , 2 ² is provided on the radius vector corresponding to the line of the line address “7”. Then, when the light from the light emitting unit 54 passes through these windows, the sensor light receiving unit 55 decodes based on the received light pattern, and a 4-bit code “7” is generated. Thereafter, the code generated by the sensor light receiving unit 55 is input to one of the comparators 121 using an IC or the like as a positioning address.

Further, a rotation / control window is further provided on the outer peripheral side on each moving radius. This window is provided for switching on and off the rotation operation of the stepping motor 51.
With the above configuration, the positioning address generated by the sensor light receiving unit 55 is input to the comparator 121, and the other input of the comparator 121 is the line address transferred from the display control circuit described above. Is entered. The comparator 121 compares the positioning address with the line address, and sends a pulse signal as shown in FIG. 12C to the stepping motor 51 based on the result.

  For example, if the transferred line address and the positioning address are different, the output of the comparator 121 becomes low, and the stepping motor 51 rotates to the rotational position that generates the positioning address that matches the line address. When the stepping motor 51 reaches a desired rotation position, light is transmitted from the rotation / control window, and this is detected by the sensor light receiving unit 55. And the sensor light-receiving part 55 returns the output of the comparator 121 to high, and makes the stepping motor 51 still.

  Along with the rotation of the stepping motor 51 as described above, the drive disk 52 and the positioning disk 53 having a common axis with the rotation also rotate. Further, along with this, the LED unit 10 also rotates, rotates to a position for projecting to a desired line, and then stops as the stepping motor 51 stops.

  As described above, by scanning the LED unit 10 with the scanning unit 50, it is possible to project a screen of a plurality of lines with one LED unit 10. At this time, by performing rotation control of the LED unit 10 using the stepping motor 51, feedback control becomes unnecessary, and a drive system for positioning can be configured at low cost.

Next, a configuration example in the case where a projector unit including the LED unit 10 and the scanning unit 50 as described above is prepared and a plurality of the projector units are used will be described.
FIG. 13 is a diagram illustrating an example of a video display device configured by arranging a plurality of projector units. FIG. 14 is a diagram illustrating a configuration example of a multi-shaped screen. FIG. 14A is a front view of the screen, and FIG. 14B is a diagram illustrating how the LED unit is scanned.

As shown in FIG. 13, in the video display device of this configuration example, the projector units 200 incorporated in the frame 210 are arranged in three stages both vertically and horizontally.
The projector unit 200 includes the LED unit 10 and the scanning unit 50, and functions as a display module that displays a single screen, such as a screen composed of 32 horizontal pixels × 16 vertical pixels. The screen size can be arbitrarily set according to the size of the screen 100.

  The projector unit 200 described above is incorporated in a frame 210 and arranged vertically and horizontally, and one screen 100 is disposed on the front surface thereof. As a result, a screen corresponding to each projector unit 200 is projected onto the screen 100, and a multi-sized large screen is projected onto the screen 100 as shown in FIG.

  By adopting such a configuration, it is possible to prevent the seam between the screens from being directly visually recognized, so that the appearance can be improved. Further, even when a large screen is configured as described above, a good screen with little luminance unevenness can be obtained.

  As described above, in the video display device of the present embodiment, the LEDs 1 are arranged in the horizontal direction to constitute the LED unit 10, and this is scanned in the vertical direction to project the video on the screen 100. By doing in this way, LED1 itself becomes a light source which emits the light according to video data, and since the point light source which emits strong light like the conventional one becomes unnecessary, an apparatus structure can be simplified. In addition, since the light emitted from each LED 1 is projected almost parallel to the screen 100, the luminance unevenness in each line is sufficiently reduced, and a good screen with little luminance unevenness can be obtained.

  In general, LEDs can be adjusted for individual brightness using voltage or current. Therefore, by configuring the LED unit 10 using the LEDs 1, if the luminance of each LED corresponding to the three primary colors is individually adjusted, there is an advantage that color unevenness in the screen is reduced. In particular, when a multi-configuration such as the above example is configured, color unevenness is more noticeable than when a single screen configuration is used. A good screen with little unevenness can be obtained.

In the above description, the LED is used as the light emitting element having directivity. However, any other light emitting element having directivity may be used.
In the above description, the LEDs 1 are arranged in the horizontal direction, but may be arranged in the vertical direction. In this case, scanning is performed in the horizontal direction.

In the above description, one LED unit 10 is arranged on one screen 100 for scanning, but a plurality of LED units 10 may be arranged.
Furthermore, in the above description, scanning of each line is performed once in one frame. However, in order to suppress flicker of line scanning, it may be performed a plurality of times in one frame.

  15A and 15B are diagrams showing examples of display patterns for the purpose of preventing flicker. FIG. 15A is a diagram showing an example of a display pattern that is turned on for each pixel, and FIG. 15B is a diagram showing how it is viewed in one frame. It is.

  In the example of FIG. 15, after one pixel is displayed in each line during a certain period in one frame, the above is displayed alternately during the other period. By performing such display a plurality of times during one frame period, one screen is constituted by one frame as shown in FIG. Thus, by performing scanning of each line a plurality of times in one frame, the lighting cycle of each line is shortened, and flickering of line scanning can be suppressed.

(Second Embodiment)
16A and 16B are diagrams showing a video display apparatus according to the second embodiment of the present invention, in which FIG. 16A is a diagram showing a configuration example of a screen, and FIG. 16B is a side view. FIG. 17 is a front view of the LED unit used in the present embodiment.

The video display device according to the present embodiment includes a screen 100, an LED unit 20 disposed behind the screen 100, and a mirror 21.
The LED unit 20 faces in the opposite direction to the screen 100 and is fixed so as not to move further. In the present embodiment, as shown in FIG. 17, LEDs 1 arranged in a horizontal direction are arranged vertically, and LED 1 arranged on the upper side is LED light emitting unit 20 a, and LED 1 arranged on the lower side is arranged. Let it be LED light emitting part 20b. The LED light emitting units 20a and 20b are configured to emit light at predetermined angles upward and downward with respect to the horizontal direction, respectively.

  The mirrors 21 are respectively provided above and below the screen 100 with the LED unit 20 interposed therebetween. In the present embodiment, each mirror 21 rotates around a central axis parallel to the arrangement direction of the LEDs 1, and the reflection direction of the light emitted from the LED light emitting units 20 a and 20 b depends on the projection position on the screen 100. Change each. As described above, each mirror 21 has a function of scanning the light emitted from the LED light emitting units 20a and 20b in a direction orthogonal to the arrangement direction of the LEDs 1.

  In such an image display device, light corresponding to each line displayed on the upper half of the screen 100 is emitted from the LED light emitting unit 20a. Similarly, light corresponding to each line displayed on the lower half of the screen 100 is emitted from the LED light emitting unit 20b. In the present embodiment, the LED light emitting units 20a and 20b emit light corresponding to lines that are symmetrical with respect to the center of the screen 100, such as the upper line 1 and the lower line 1 of the screen 100, for example. Shall be released at the same timing.

  Here, it is assumed that each mirror 21 is set at a certain angle, and the light reflected there is projected onto the upper and lower lines 1 of the screen 100, respectively. Thereafter, each mirror 21 rotates by a predetermined angle so that the light from the LED light emitting units 20a and 20b is projected to the positions of the upper and lower lines 2, respectively. Then, at the moment when the rotation is finished, light corresponding to the video data of the upper and lower lines 2 is emitted from the LED light emitting units 20a and 20b, reflected by the mirrors 21, and then projected to the positions of the upper and lower lines 2, respectively. The By repeating such an operation, each line is scanned in the vertical direction and projected onto the screen 100 as an image.

  Thus, since the light from each LED 1 is projected on the screen 100 in a substantially parallel manner, luminance unevenness in the line can be sufficiently reduced. Furthermore, by scanning such a line by the rotation of the mirror 21, a good screen with little luminance unevenness can be obtained.

Next, the angle set for the mirror 21 will be described.
FIG. 18 is a diagram for deriving the angle set for the mirror. This figure shows a state in which the light emitted from the LED light emitting unit 20a is reflected by the mirror 21 disposed on the upper side.

  The distance from the central axis of the mirror 21 to the screen 100 is X, and the distance between each line on the screen 100 is Y0. In addition, the projection angle of light emitted from the LED light emitting unit 20a is β. In the example of FIG. 18, the reflected light beam from the mirror 21 is projected on a line located at a distance of nY0 (n is an integer) from the position of the perpendicular line dropped from the center of the mirror 21 to the screen 100 as a reference. At this time, if the reflection angle at the mirror 21 is α and the angle between the reflected light beam and the screen 100 is γ, the following equation is established.

α = β + γ−90 (3)
α / 2 = 90−θn− (90−β) = β−θn (4)
Substituting equation (3) into α in equation (4) yields the following equation.

θn = β−α / 2 = 1/2 (β + 90−γ) (5)
Here, since tan γ = X / nY0,
θn = 1/2 (β + 90−tan ⁻¹ (X / nY0)) (6)
Is obtained.

  Therefore, by setting the angle θn of the mirror 21 rotating around the central axis as shown in Expression (6) according to the position of the line displayed on the screen 100, the light emitted from the LED light emitting unit 20a is The light is reflected so as to be projected at a desired line position on the screen 100. Then, by rotating the mirror 21 so as to have an angle corresponding to each line, scanning is performed in the vertical direction of the screen 100.

  In the above description, the setting angle of the mirror 21 disposed on the upper side is derived and the light from the LED light emitting unit 20a is scanned. However, the setting angle of the mirror 21 disposed on the lower side is similarly derived. The same scanning is performed on the LED light emitting unit 20b.

  In this way, light emitted from the LED light emitting units 20a and 20b of the LED unit 20 can be scanned in the vertical direction, and a screen of a plurality of lines can be projected by the single LED unit 20.

Further, a projector unit including the LED unit 20 and the mirror 21 as described above is prepared, and arranged in the vertical and horizontal directions, thereby forming the multi-screen as described above.
FIG. 19 is a diagram showing a configuration example of a multi-shaped screen configured using the LED unit of the present embodiment, (A) is a front view of the screen, and (B) is a scanning state of the LED unit. FIG.

  In the example of FIG. 19, the projector unit including the LED unit 20 and the mirror 21 according to the present embodiment is incorporated in a frame similar to the above as in the multi-image display device described above, and further, it is 3 in both vertical and horizontal directions. Assume that they are lined up.

Thus, even when a multi-shaped screen is configured using the LED unit 20 of the present embodiment, the same effects as described above can be obtained.
As described above, the video display device according to the present embodiment reflects the light emitted from the fixed LED unit 20 by the mirror 21, and further rotates the mirror 21 according to the position of the projected line. Thus, the scanning is performed in the vertical direction of the screen 100. By doing in this way, similarly to the video display apparatus described above, the apparatus configuration can be simplified and the luminance unevenness in the screen can be reduced. Further, the light emitted from the LED unit 20 is folded back by the mirror 21 and projected onto the screen 100. Therefore, the projection distance to the screen 100 can be shortened and the apparatus depth can be reduced as compared with the above-described video display apparatus.

FIG. 20 is a diagram illustrating a video display device according to a modification of the second embodiment.
The video display device according to this modification has a plate-like body 22 that moves up and down in parallel to the vertical direction, and a plurality of mirrors 21 are provided on the plate-like body 22. Is different.

  Each mirror 21 is attached to each line displayed on the screen 100 at an angle satisfying the above formula (6) with respect to the plate surface, and a reflection angle corresponding to the position of the projected line. Is set.

  The plate-like body 22 provided with the mirror 21 is moved and stopped in the vertical direction according to the scanning timing so that the light from the LED light emitting unit 20a is reflected by each mirror 21. And when it stops, the light according to a predetermined line is emitted from LED light emission part 20a. For example, when the plate-like body 22 stops at the position of the mirror 21 attached at the angle θn, light corresponding to the line of the distance nY0 is emitted from the LED light emitting unit 20a. A plate-like body (not shown) is arranged on the lower side in the same manner as described above, and the light from the LED light emitting unit 20b is also scanned in the same manner as described above.

In this way, a good screen with less luminance unevenness can be obtained.
FIG. 21 is a diagram illustrating a video display apparatus according to another modification of the second embodiment.
The video display device according to this modification has a rotating body 23 that rotates about a rotation axis parallel to the arrangement direction of the LEDs 1, and a plurality of mirrors 21 are provided on the periphery of the rotating body 23. It is different from the video display device of the modification.

  Each mirror 21 is attached to each line displayed on the screen 100 at an angle satisfying the above formula (6) with respect to the tangent line, and a reflection angle corresponding to the position of the projected line is set. Is set.

  Thus, the rotating body 23 provided with the mirror 21 is rotated and stopped according to the scanning timing so that the light from the LED light emitting unit 20a is reflected by each mirror 21. And when it stops, the light according to a predetermined line is emitted from LED light emission part 20a. For example, when the rotating body 23 stops at the position of the mirror 21 attached at the angle θn, the light corresponding to the line of the distance nY0 is emitted from the LED light emitting unit 20a. Note that a rotating body (not shown) is also arranged on the lower side in the same manner as described above, and the light from the LED light emitting unit 20b is also scanned in the same manner as described above.

  In this way, a good screen with less luminance unevenness can be obtained. Further, since the position is determined by the rotational movement rather than the vertical movement as in the above-described modification, it is possible to save time for returning to the original place every time the scanning is completed, and positioning can be performed easily. .

1 is a side view showing an outline of a video display device according to a first embodiment of the present invention. It is a figure which shows the structure of the LED unit used for this Embodiment, (A) is a front view, (B) is a top view. It is a side view for demonstrating the scanning of the video display apparatus of this Embodiment. It is a figure which shows the example of a screen structure of the video display apparatus of this Embodiment, (A) is a front view of a screen, (B) is a side view which shows the mode of a scanning of an LED unit. It is a figure which shows the structural example of the circuit for display control of the video display apparatus of this Embodiment. It is a figure which shows the example of transfer of a line address. It is a figure which shows the example of transfer of video data. It is a figure for deriving the angle set up to an LED unit. It is a graph which shows the relationship between the position of each line displayed on a screen, and the angle of an LED unit. It is a top view which shows the structural example of a scanning part. It is an A direction arrow directional view of FIG. It is a figure which shows the detail of the disk for positioning and the window provided in this, (A) is a front view, (B) is the figure which expands and shows the detail of a window on a straight line, (C) has passed the window It is a figure which shows an example of the pulse produced | generated based on light. It is a figure which shows an example of the video display apparatus comprised by arranging multiple projector units. It is a figure which shows the structural example of a multi-shaped screen, (A) is a front view of a screen, (B) is a figure which shows the mode of the scanning of an LED unit. It is a figure which shows the example of a display pattern aiming at flicker prevention, (A) is a figure which shows the example of the display pattern lighted for every pixel, (B) is a figure which shows the appearance in 1 frame. It is a figure which shows the video display apparatus of the 2nd Embodiment of this invention, (A) is a figure which shows the structural example of a screen, (B) is a side view. It is a front view of the LED unit used for this Embodiment. It is a figure for deriving the angle set up to a mirror. It is a figure which shows the structural example of the multi-shaped screen comprised using the LED unit of this Embodiment, (A) is a front view of a screen, (B) is a figure which shows the mode of the scanning of an LED unit. . It is a figure which shows the video display apparatus of the modification of 2nd Embodiment. It is a figure which shows the video display apparatus of another modification of 2nd Embodiment.

Explanation of symbols

1 LED
10, 20 LED unit 21 Mirror 50 Scanning unit 100 Screen

Claims (1)

In a video display device that projects video from the back of the screen,
A light-emitting unit that is arranged on the back side of the screen and has light-emitting elements that have directivity and emit light according to a video signal;
A scanning unit that is disposed on the back side of the screen and scans the light emitted from the light emitting unit in a direction orthogonal to the arrangement direction of the light emitting elements;
Have
The scanning unit includes a reflection unit that reflects the light and projects the light onto the screen.
The scanning unit has a plate-like body that translates in the scanning direction of the light, and the plate-like body has a plurality of reflection means each having a reflection angle determined according to a projection position of the light on the screen. Is provided according to the scanning direction ,
The light emitting unit is disposed between the screen and the scanning unit, and emits the light to the reflecting unit of the scanning unit, and the emitted light is reflected by the reflecting unit to be back of the screen. A video display device that is projected onto the screen.

Images