TEL: 02-2290-2636 FAX: 02-2290-2638 www.litepa.com.tw

Energy-saving

LED Display

Background of Design Established from 2002, Lite Pa Co., Ltd. has endeavoured in technology and application of LED display. We also propose the new method for LED driver, signal transmission, and control system. For recent years, the LED components and its packaging tech has improved which boosts up the light efficiency of white-light LED, higher than that of red, green and blue LED. Meanwhile, the issue of environmental protection and energy saving indeed applies pressure to LED video wall. Under this circumstance, Lite Pa proposed a new LED control method, Pre-Synthesize. It applies four color system of YUV color mode instead of the traditional RGB color mode system in LED video wall. Also, we obtain the patent of this new application.

Features Energy-Saving

Sharpness

Compatibility of Black/white and color images

Lite Pa Energy-saving RGBW LED Display

Energy-saving 33.2%(Ave.)~66.6%(Max.)

Lower down the strict requirement for RGB lightness proportioning

The average lighting time of the LED lamps in RGBW display is half than the time of LED lamps in RGB display.

Traditional vs New LED Display Intro of Theory

Traditional display: based on RGB color mode Yellow = Red + Green Purple = Red + Blue Indigo = Green + Blue White = Red + Green + Blue

RGB as one pixel in traditional LED PCB.

New display method based on YUV color mode:

RGBW as one pixel in new LED PCB.

Y R-Y G-Y B-Y

Brightness measure aberration measure aberration measure aberration measure

Math deduction analysis & Application to product Math deduction analysis Based on the previous equation, if a, b, c doesn’t equal to zero, then three basic colors can mix. Remove the least among a, b, c and add white. The white can mix with the other two colors.

They could be like the below: (1) a=b=c color_out＝a*W (2) a=b <c color_out＝a*W+|c-a|*B (3) a=c < b color_out＝a*W+|b-a|*G (4) b=c < a color_out＝b*W+|a-b|*R (5) a<b<c (They don’t equal to each other.) color_out＝a*W+(b-a)*G+(c-a)*B (6) b<a<c (They don’t equal to each other.) color_out＝b*W+(a-b)*R+(c-b)*B (7) c<a<b (They don’t equal to each other.) color_out＝c*W+(a-c)*R+(b-c)*G The rest can be deducted by analogy.

Application to product

Energy-Saving Mode Color saturation not affected. Requirement R-30 / G-40 / B-50，the actual display status would be R-0 / G-10 / B-20 / W-30 color-out = dW+(a-d)R+(b-d)G+(c-d)B This is under Energy-Saving mode

Brightness Mode Sacrificing color brightness lifted. Requirement R-30 / G-40 / B-50， brightness lifted 20，the actual display status would be R-30/ G-40/ B-50 / W-20 Brightness lifted: color out = aR+bG+cB+(manually increase 0~100%)W

Compare the current (1) As LED characteristics, the light-emitting efficiency of White LED is higher than RGB LEDs. We can just place White LED directly to subsitute the white light of mixturing RGB LEDs. Due to the same current consumption at each LED, when raising the light-emitting efficiency of white light, RGBW will save more energy than RGB.

The common light efficiency as below: Driving current＝20mA Beam angle＝100*50

LED

RED

GREEN

BLUE

WHITE

Brightness (mcd)

620

1200

280

2200

Based on the previous: (1) a=220 b=220 c=220 color out＝220*W (black & white)

current

(2) a=128 b=128 c=200 color out＝128*W+72*B (single-color saturation)

current

current

(3) a=32 b=80 c=200 color out＝32*W+48*G+168*B (Any two of the three basic colors mixture) (4) In other situation, any one or two of a, b, c is zero without white-light LED lit up, the power consumption is the same.

New

New

current

The Same

17mA

19mA

Energysaving

66.6%

56.1％

Energysaving

24 ％

Energysaving

0％

Compare the current (2) Statistics for image color: Three color mixture TV shows/ movie Test on spot

Item

Spec

Two color mixture

68% Energy-saving

Single color mixture

28%

4%

35%~42%

P16 full color/ static driving/ resolution8 00*600/（calculated in RMB） RGB system

RGBW system

Energy-saving

Consumption

86KW

53KW

38%

Daily consumption (8hrs/day）

688/550 dollars

424/339 dollars

211 dollars

Annual consumption

251120/0.2 million dollars

154760/0.12 million dollars

80 thousand dollars

Lifespan (8 years/ unit)

2008960/1.6 million

1238080/0.96 million dollars

640 thousand dollars

Compare the image Sharpness When the image is synthesized in brightness and aberration, human eyes have good identification to black and white, and thus the sharpness can be boosted and itâ&#x20AC;&#x2122;s more obvious with closer look.

RGB system

RGBW system

Lift up the lifespan of the display The experiment of the complete image synthesized by brightness and aberration measure testifies that human eyes have lower identification to the details of full color image than those of black and white. ● In RGB system, any of the three colors decays, the aberration of brightness will be noticed by human eyes easily. ● In RGBW, any of the four colors decays, the brightness measure isn’t affected. ● The average lighting time of the LED lamps in RGBW display is half than the time of LED lamps in RGB display. The above features can prolong the lifespan of display. The original image

RGB system

RGBW system

Compatibility Compatibility of black & white & full color

Compatibility of the PCB Driver IC：8 bits or 16 bits w/ constant current, MBI5026 / ST2221 Driving：Same decoding, static or 1/2,1/4,1/8,1/16 driving LED allocation：Rectangle/ vertical/ horizontal

The original image

RGB system

RGBW system

To separate brightness signal into RGB measure, not compatible to the original system.

No need to change the system which is compatible to the original system.

RGB system

RGBW system

Compare the cost Sample specification:  Pitch：P16  Resolution：32*32  Driving：Static driver

Item

System

RGB system

RGBW system

LED

2048R/1024G/1024B

1024R/1024G/1024B/1024W

Driver IC (mbi5026)

192/256*

256

PCB size

Same

Same

Power

307W

200W

Total cost

*****

5~7% increased

● In visual display mode, 256 driver IC are applied but in actual display mode, 192 driver IC are applied.

Compare the light effect of image Left: RGB/ Right: RGBW

Red 255

Blue 255

Green 255

White 255 (6500K)

Energy-saving RGBW LED Display

Energy-saving RGBW LED Display