Light source driving device and display device

A light source driving and light source technology, applied in optics, optical components, static indicators, etc., can solve the problems of minimum current increase, inability to ensure display brightness, and difficulty in achieving low brightness display, and achieve the effect of ensuring dynamic range.

Active Publication Date: 2016-08-24
NIPPON SEIKI CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In the display device using the FSC method, since a large amount of light must be irradiated to the display element in a short time, unless a high-output type light source (such as an LED with a maximum rated current of several amperes) is not used, the display brightness cannot be ensured.
However, if a high output type light source is used, the minimum current to guarantee light emission also increases
As a result, it is difficult to achieve stable low-brightness display, and cannot ensure a dynamic range from high-brightness to ultra-low-brightness

Method used

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  • Light source driving device and display device
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  • Light source driving device and display device

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Experimental program
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no. 2 Embodiment approach

[0120] In the embodiment described above, the light source driving device 5 inputs the light intensity detection signal SFB from the light intensity detection unit 500 as a feedback signal into the comparison circuit 410, and the comparison circuit 410 detects the light intensity from the light intensity detection unit 500. The signal SFB is compared with the reference signal SA from the first control unit 100 to form a comparison signal SB as a pulse signal, and the light source driving device 5 of the second embodiment is different in that: Figure 10 As shown, the driving currents lr, lg, lb flowing through the light source 11 are detected by the current detection unit 600, a voltage value is calculated based on the current detection unit 600, and a voltage signal VFB related to the voltage value is output to the comparison circuit 410 as a feedback signal.

[0121] The comparison circuit 410 of the second embodiment compares the voltage signal VFB input from the current det...

no. 3 Embodiment approach

[0124]In the above-mentioned embodiment, the light source driving mechanism 400 outputs the lighting signal SD1 only in the predetermined driving period T for each sub-frame, but the light source driving device 5 of the third embodiment is different in that only the The lighting signal SD1 is output for the number U of pulses determined for each sub-frame. That is, switching timings of the enable signal SC1 (disable signal SC2 ) output from the second control unit 200 to the logic circuit 420 are different. Next, the switching operation of the enable signal SC1 (disable signal SC2 ) of the second control unit 200 in the third embodiment will be described using the timing chart of FIG. 11 .

[0125] The second control unit 200 controls the limit signal SC (permission signal SC1) in such a manner that only a predetermined number of pulses U (U1 in FIG. Or the prohibition signal SC2) is output to the logic circuit 420. Specifically, the second control unit 200 starts counting t...

no. 4 Embodiment approach

[0127] In addition, in the above-mentioned embodiment, the second control unit 200 determines the presence or absence of the non-lighting signal SD2 (prohibition signal SC2 ) in the limit signal SC based on the value of the external illuminance signal SL. However, the second control unit 200 of the fourth embodiment The control unit 200 controls the proportion of the prohibition signal SD2 in each sub-frame period based on the value of the external illuminance signal SL. Figure 12 is a timing diagram showing how T changes during the driving period according to the value of the external illuminance signal SL. It is a diagram showing the state of the limit signal SC at different times. 12( b ) shows a case where the external illuminance signal SL is large (large dimming value), and FIG. 12( c ) shows a case where the external illuminance signal SL is small (small dimming value). Specifically, for example, the second control unit 200 of the fourth embodiment reduces the proporti...

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Abstract

In the present invention, it is possible to precisely adjust the intensity of light emitted from a light source and ensure a dynamic range from high brightness to low brightness even in a field-sequential color drive format for turning light on and off at high speed. A light intensity detection signal (SFB) indicative of the intensity of light emitted by a light source (11) is acquired, and on the basis of the light intensity detection signal (SFB) and a set reference signal (SA), a comparison circuit (410) generates a comparison signal (SB) indicative of turning ON and OFF. Within a sub-frame period, a logic circuit (420) repeats turning ON / OFF based on a pulse signal inputted from the comparison circuit (410), and outputs a lighting signal (SD1) for causing the light source (11) to emit light in accordance with the reference signal (SA) which is a set value, and outputs a non-lighting signal (SD2) for causing the light source (11) to not emit light in accordance with a set value.

Description

technical field [0001] The present invention relates to a display device, in particular, the present invention relates to a display device for displaying images in a field sequential color manner and a light source driving device for it. Background technique [0002] As a display device for displaying images by the field sequential color method (hereinafter referred to as "FSC"), Patent Document 1 discloses a type using a DMD (registered trademark: Digital Micro-mirror Device) as a reflective display element. . Such a display device realizes high-resolution display by reflecting light emitted from a light source by each reflector included in the DMD based on an image signal from the outside. [0003] In the display device using the FSC method, since a large amount of light must be irradiated to the display element in a short time, unless a high-output type light source (for example, an LED with a maximum rated current of several amperes) is used, the display brightness cann...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G09G3/34B60K35/00G09G3/20
CPCG09G3/3413G09G2310/0235G09G2320/064G09G2360/144G09G2360/145B60K35/00G02B27/0101G02B2027/0118G02B2027/014G09G2310/08G09G2320/0626G09G2360/14
Inventor 仓石友也秦诚
Owner NIPPON SEIKI CO LTD
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