Patent Publication Number: US-2018040280-A1

Title: Laser light regulation system

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a light regulation system, and in particular to a laser light regulation system, for which the luminance of images emitted can be adjusted based on the ambient light luminance. 
     The Prior Arts 
     In this respect, as an example of the Prior Art, U.S. Pat. No. 9,167,655 disclosed a Backlight Adjustment System. Refer to  FIG. 1  for a perspective view of an exemplary electronic display. As shown in  FIG. 1 , the system includes an ambient light sensor  170 , a back light sensor  171 , and a temperature sensor  175 . When backlight is emitted from a backlight unit  120 , the software driver  190  will send a signal to a current measurement device  200  to measure the current delivered by the power source  195 , and send back the information to the software driver  190 . In turn, the software driver  190  will send instructions to the power source  195 , to regulate the power sent to the current measurement device  200  and the backlight unit  20 , in achieving adjustment of light luminance of the backlight unit  120 . 
     In another example of the Prior Art, Taiwan Patent No. 1462648 disclosed a Backlight Driving Circuit and a Backlight Driving Method. Refer to  FIG. 3  for a flowchart of the steps of a single loop circuit charging method. As shown in  FIG. 3 , firstly, in Step S 410 , a control circuit  105  controls the power source VS to provide voltage to an anode of a light-emitting-diode (LED)  102 . Next, in step S 420 , a light sensitive element  104  senses the luminance of the ambient light, and is disposed between the cathode of the light-emitting-diode  102  and the ground, while its electric resistance can be varied based on the ambient light luminance of the electronic device. And finally, in step S 430 , the control circuit  105  regulates the output voltage of the power source VS, to control luminance of the light-emitting-diode  102  based on the feedback voltage VFB of the LED  102 . 
     In yet another example of the Prior Art, U.S. Pat. No. 8,848,289 disclosed a Near-To-Eye Display With Diffractive Lens, that includes a waveguide  205 , a polarizer  215 , a wire grid polarizer  210 , and a collimating lens  255 . In such a structure, the polarizer  215  is capable of controlling the wire grid polarizer  210  based on the variations of the ambient light, to regulate luminance of the images emitted from the waveguide  205 . Then, the images transmitted through the collimating lens  255  may enter into viewer&#39;s eyes, for the viewer to view the images clearly. 
     In a further example of the Prior Art, U.S. Pat. No. 8,436,952 discloses a Hybrid Illumination System For Head-Up Display, comprising one or more optics units  110 , a light mixing unit  170 , a condensing unit  180 , a polarizing beam splitter  190 , and a reflective display unit  200 . In such a device, the one or more optics units  110  guides the ambient light into the light mixing unit  170 , which homogenizes all the lights therein, and outputs the lights to the condensing unit  180 , that condenses the lights and then outputs them to a polarizing beam splitter  190 . Through the polarizing beam splitter  190  and the reflective display unit  200 , the modulated lights are projected onto a windshield to form images, in realizing a Head Up Display (HUD). 
     In a final example of the Prior Art, U.S. Pat. No. 7,203,005 disclosed a Head Up Display (HUD) system  100 , including a polarized image generating system  110 , a polarization preserving rear projection screen  120 , and a polarizing reflector  130  on a windshield  100 . In this HUD system  100 , polarizing reflector  130  and projection screen  120  are utilized to raise luminance of the display, so that the display may have low haze and high light transmittance, thus suitable to be used as a windshield of a vehicle. 
     However, the light emitting devices of the Prior Art mentioned above are not able to avoid effectively the problem that, the images emitted in high ambient light luminance tend to appear blurring, while the images emitted in low ambient light luminance tend to appear dazzling to the viewer. 
     Therefore, presently, the design of the light emitting device is not quite satisfactory, and it leaves much room for improvement. 
     SUMMARY OF THE INVENTION 
     The objective of the present invention is to provide a laser light regulation system, that is capable of regulating automatically luminance of the images emitted, based on the luminance of ambient light, so that in daytime or nighttime, the images emitted will not appear to be blurring or dazzling to a viewer. 
     In order to achieve the objective mentioned above, the present invention provides laser light regulation system, including an image processor; an ambient light sensor; a luminance mode determination circuit, connected electrically to the ambient light sensor; a laser driving circuit, connected electrically to the image processor; a laser light source, connected electrically to the laser driving circuit to emit laser lights; a luminance control module, connected electrically to the luminance mode determination circuit; a scanner driving circuit, connected electrically to the image processor; and an MEMS (micro-electromechanical system) scanner, controlled by the scanner driving circuit to perform scanning, and to reflect the laser light coming from the polarizer. 
     The luminance control module includes a luminance control circuit, a liquid crystal, and a polarizer. Alternatively, it may include a luminance control circuit, a driving motor, and a polarizer. In application, the luminance control module receives a luminance mode signal from the luminance mode determination circuit, to adjust further luminance of the projected images. 
     Further scope of the applicability of the present invention will become apparent from the detailed descriptions given hereinafter. However, it should be understood that the detailed descriptions and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the present invention will become apparent to those skilled in the art from the detailed descriptions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The related drawings in connection with the detailed descriptions of the present invention to be made later are described briefly as follows, in which: 
         FIG. 1  is a perspective view of an exemplary electronic display according to the Prior Art; 
         FIG. 2  is a flowchart of the steps of a single loop circuit charging method according to the Prior Art; 
         FIG. 3  is a block diagram of a laser light regulation system according to first embodiment of the present invention; 
         FIG. 4  is a block diagram of a laser light regulation system in a high ambient luminance mode according to a first embodiment of the present invention; 
         FIG. 5  is a block diagram of a laser light regulation system in a low ambient luminance mode according to a first embodiment of the present invention; 
         FIG. 6  is a block diagram of a laser light regulation system of another configuration according to a first embodiment of the present invention; 
         FIG. 7  is a block diagram of a laser light regulation system according to a second embodiment of the present invention; and 
         FIG. 8  is a block diagram of a laser light regulation system of another configuration according to a second embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The purpose, construction, features, functions and advantages of the present invention can be appreciated and understood more thoroughly through the following detailed description with reference to the attached drawings. 
     Refer to  FIGS. 1 to 8  respectively for a block diagram showing the components for an exemplary embodiment of the control system according to the Prior Art; a flowchart of the steps of a single loop circuit charging method according to the Prior Art; a block diagram of a laser light regulation system according to a first embodiment of the present invention; a block diagram of a laser light regulation system in a high ambient luminance mode according to a first embodiment of the present invention; a block diagram of a laser light regulation system in a low ambient luminance mode according to a first embodiment of the present invention; a block diagram of a laser light regulation system of another configuration according to a first embodiment of the present invention; a block diagram of a laser light regulation system according to a second embodiment of the present invention; and a block diagram of a laser light regulation system of another configuration according to a second embodiment of the present invention. 
     Embodiment 1 
     As shown in  FIG. 3 , the present invention provides a laser light regulation system composed of a display main body  700 , which includes: an ambient light sensor  710 , a luminance mode determination circuit  720 , a luminance control module  730 , an MEMS scanner  740 , an image processor  750 , a scanner driving circuit  760 , a laser driving circuit  770 , and a laser light source  780 . Wherein, the ambient light sensor  710  is used to sense automatically the light luminance of the outside environment, and it outputs a sensed signal S 100  to the luminance mode determination circuit  720 , which outputs at least a luminance mode signal S 200  to a luminance control module  730  based on the sensed signal S 100 . The luminance control module  730  includes a liquid crystal  731 , a polarizer  732 , and a luminance control circuit  733 . The luminance control module  730  receives the luminance mode signal S 200 , while the luminance control circuit  733  controls the molecular alignment of the liquid crystal  731 . 
     Further, when the image processor  750  is activated, it will send simultaneously a first driving signal S 310  to a laser driving circuit  770 , and a second driving signal S 320  to a scanner driving circuit  760 . Upon receiving the first driving signal S 310 , the laser driving circuit  770  will output a current to activate a laser light source  780 , to make it emit laser light L 110  of an image, to the liquid crystal  731  of the luminance control module  730 . Since when the liquid crystal  731  receives the luminance mode signal S 200 , its molecular alignment has been adjusted by the luminance control circuit  733 , as such, when the laser light L 110  is received, the luminance mode signal S 200  will cause the liquid crystal  731  to output different projection luminance signals L 120  to a polarizer  732 . After the projection luminance signal L 120  is adjusted by the polarizer  732 , a projection luminance signal L 120 ′ is output. 
     The scanner driving circuit  760  outputs a third driving signal S 330  to an MEMS (micro-electromechanical system) scanner  740 , which can be of an MEMS type. Meanwhile, the MEMS scanner  740  receives the projection luminance signal L 120 ′ from the luminance control module  730 , and then the MEMS scanner  740  outputs the projection luminance signal L 120 ′ to the diffuser  800 , for it to reduce light spots in the projected image, and then it outputs the image to an image synthesizer  900  to display the image. The maximum luminance of the image is controlled and determined by the luminance mode signal. By way of example, since the system may include a high luminance mode signal and a low luminance mode signal, and in the case of low luminance mode signal, the maximum luminance of an image is only half of that as provided by the maximum signal of the system. 
     Embodiment 1—High Ambient Luminance Mode 
     Refer to  FIG. 4  for a block diagram of a laser light regulation system in a high ambient luminance mode according to a first embodiment of the present invention. As shown in  FIG. 4 , when the ambient light luminance is high, the ambient light sensor  710  will detect automatically the luminance of the light source, and outputs a sensed signal S 100  to a luminance mode determination circuit  720 , which in turn outputs high luminance mode signal S 210  to a luminance control module  730 . In the luminance control module  730 , the luminance control circuit  733  controls the molecular alignment of the liquid crystal  731 , and it utilizes the laser light L 110  received to output a high projection luminance signal L 121  to the MEMS scanner  740 , which in turn outputs the high projection luminance signal L 121  to a diffuser  800 , for it to reduce light spots in the projected image, and then it outputs the image to an image synthesizer  900  to display the image, so that a viewer may view clearly the information contained in the projected image without feeling blurring, even in the condition of high ambient light luminance. 
     Embodiment 1—Low Ambient Luminance Mode 
     Refer to  FIG. 5  for a block diagram of a laser light regulation system in a low ambient luminance mode according to a second embodiment of the present invention. As shown in  FIG. 5 , when the ambient light luminance is low, the ambient light sensor  710  will detect automatically the luminance of the light source, and outputs a sensed signal S 100  to a luminance mode determination circuit  720 , which in turn outputs a low luminance mode signal S 220  to a luminance control module  730 . In the luminance control module  730 , the luminance control circuit  733  controls the molecular alignment of the liquid crystal  731 , and it utilizes the laser light L 110  received to output a low projection luminance signal L 122  to the MEMS scanner  740 , which in turn outputs the high projection luminance signal L 121  to a diffuser  800 , for it to reduce light spots of the projected image, and then it outputs the image to the image synthesizer  900  to display the image, so that a viewer may view clearly the information contained in the projected image without feeling dazzled, even in the condition of low ambient light luminance. 
     Refer to  FIG. 6  for a block diagram of a laser light regulation system of another configuration according to a first embodiment of the present invention. Wherein, the luminance control module  730  can be of another configuration. In application, upon receiving the luminance mode signal S 200 , the luminance control circuit  733  controls the driving motor  734 , to drive the polarizer  732  connected electrically into rotation. As such, the driving motor  734  drives the polarizer  732  into rotating to various angles based on the luminance mode signal S 200 . When the laser light L 110  output by the laser light source  780  reaches the polarizer  732 , the driving motor  734  drives the polarizer  732  to rotate to various angles, such that it outputs the projection luminance signal L 120 ′ of various intensities to the MEMS scanner  740 . 
     Embodiment 2 
     Moreover, refer to  FIG. 7  for a block diagram of a laser light regulation system according to a second embodiment of the present invention. As shown in  FIG. 7 , the MEMS scanner  740  is placed in front of the luminance control module  730 , such that when the laser light L 110  is projected onto the MEMS scanner  740 , it will receive a third driving signal S 330  at the same time, and outputs a laser light L 110 ′ to the liquid crystal  731  and polarizer  732  of the luminance control module  730 . The luminance mode determination circuit  720  outputs a luminance mode signal S 200 , and that is used to control the luminance control circuit  733 , for it to control the molecular alignment of the liquid crystal  731 . As such, when the laser light L 110 ′ is projected onto the liquid crystal  731 , through different molecular alignments of the liquid crystal  731 , the value of the projection luminance signal L 120 ′ projected out from the luminance control module  730  can be varied. Finally, the luminance control module  730  outputs the projection luminance signal L 120 ′ to a diffuser  800 , for it in turn outputs the projection luminance signal L 120 ′ to the image synthesizer  900  to display the image. 
     Refer to  FIG. 8  for a block diagram of a laser light regulation system of another configuration according to a second embodiment of the present invention. As shown in  FIG. 8 , the luminance control module  730  can be of another configuration. In application, upon receiving the luminance mode signal S 200 , the luminance control circuit  733  controls the driving motor  734 , to drive the polarizer  732  into rotating to a corresponding angle. Then, the laser light L 110 ′ output from the MEMS scanner  740  is transmitted through the polarizer  732 , and then it is output as the projection luminance signal L 120 ′ to the diffuser  800  to reduce the light spot in the projected image. Then, the signal is output and transmitted to the image synthesizer  900  to display the image. 
     The laser light regulation system of the present invention is suitable to use in a Head Up Display (HUD) of a vehicle, to detect the luminance of ambient light outside the vehicle, and to automatically adjust the images on the Head Up Display (HUD) to a proper luminance in broad day light and at night, without causing blurring or dazzling to the driver, thus improving driving safety. 
     The above detailed description of the preferred embodiment is intended to describe more clearly the characteristics and spirit of the present invention. However, the preferred embodiments disclosed above are not intended to be any restrictions to the scope of the present invention. Conversely, its purpose is to include the various changes and equivalent arrangements which are within the scope of the appended claims.