Display devices have been used for many years as a means of HMI (Human Machine Interface) to connect humans and machines interactively, and their usage are still expanding.
Automotive interiors are no exception to this trend, with an increasing amount of information being displayed,ranging from important information for safe driving to entertainment information, and this trend will continue to evolve further in the future.
The LCD (Liquid Crystal Display) screen of a meter or entertainment system is a full-color display, with white LED backlight light passing through the LCD's color filter (the three primary colors of light: R: red, G: green, and B: blue).Even if the display device (LCD) is the same, the light source used for the backlight changes the display quality and power consumption characteristics.
| Normal White LEDs |
Normal white LEDs achieve white light by mixing blue LED light with yellow phosphor. They feature low power consumption due to their extremely high efficiency in converting power into light, and are relatively inexpensive due to the small number of constituent materials used.On the other hand, the red light component is small, so the coloring performance of the red area when transmitted through an LCD is not high.
| Wide Color Gamut White LED |
White light is achieved by mixing blue LED light with green and red phosphors.The LED light component matches the LCD color filter, resulting in particularly vivid coloring around the red area, expanding the color gamut and improving the quality. On the other hand, the power consumption tends to increase due to the lower power-to-light conversion efficiency compared to normal white LEDs.
White light from the backlight can be seen as a color image by passing through the LCD and color filter.
| Normal white light |
Normal white light with blue light + yellow phosphor has a low red component light, so red and reddish dislpay on the screen may appear dull.
| Wide gamut white light |
Wide gamut white light with blue light + green phosphor + red phosphor makes screen colors look more vivid than normal white light because of its high red component.
LCDs are made visible as a luminescent display by transmitting light from the back of the LCD through the backlight. The following describes two typical layout for LEDs, which are the light source of the backlight, used in automotive applications.
LED light is emitted from the side to the light guide plate placed under the LCD, and the light is extracted from the plate upward (toward the user).
Features
• The entire backlight emits light from the surface.
• Relatively small number of LEDs to be used = low power consumption
• Less uneven brightness and uniform appearance (The backlight also emits light even in areas where there is no display.)
A method in which LEDs are placed directly under the LCD display and light is directed toward the user.
Features
• Aggregation of area emission of each LED
• The number of LEDs increases depending on the display size and the illumination area of each LED.
• The brightness of the entire display can be increased according to the number of LEDs.
Local dimming technology
• By controlling light emission finely for each area, it is possible to light only necessary areas efficiently.
• High-contrast and high-definition display is possible by de-illuminating areas where there is no display.
Edge-lit/Light-guide
Slight light escapes from the unlettered black background, because the light guide plate behind the LCD uniformly illuminate.
Direct-lit
The direct local dimming method allows high-contrast, clear viewing without light in areas other than the text.
Areas without lettering display a clear black color because the backlight does not emit any light.
We have LED light sources suitable for both edge-lit and direct-lit backlight.
The appropriate light source can be selected according to the application and specifications.
| Type | Normal white | Wide color gamut white | ||
|---|---|---|---|---|
| Product name | BXMW115HGSE-100 | BXMW115HGSE-200 | BXMW115HGSE-300 | BXMW115HGSE-400 |
| Product |  |
|||
| Luminous flux (lm) | 36 | 50 | 31.5 | 44.5 |
| Forward current (mA) | 80 | 120 | 80 | 120 |
| Directivity | x=115, y=115 | x=115, y=115 | x=115, y=115 | x=115, y=115 |
| Size (L x W x H) | 3.2×1.4×0.58 mm | 3.2×1.4×0.58 mm | 3.2×1.4×0.58 mm | 3.2×1.4×0.58 mm |
| Click here for details | ||||
| Under development | |||
| Type | Wide color gamut white | ||
|---|---|---|---|
| Product name | VLJW115LCS | VXFW115JCR | VLKW115MCR |
| Product |  |
 |
 |
| Luminous flux (lm) | 1.9 | 6.6 | 22 |
| Forward current (mA) | 3 | 10 | 30 |
| Directivity | x=115, y=115 | x=180, y=180 | x=180, y=180 |
| Size (L x W x H) | 0.8×0.8×0.56 mm | 1.0×1.0×0.95 mm | 1.5×1.5×1.40 mm |
| Click here for details | |||
*Specifications are subject to change without notice as the product is still under development.
If you have any requests or questions, please feel free to contact us.
