The effect of the reflective property of a reflection film on the performance of backlight units with quantum-dot films for LCD applications

Figures & data

Figure 1. (Color online) (a) Experimental setup for measuring the angular dependence of the luminance of the backlight units with QD films that had different configurations. (b) Cross-sectional schematic figure of one of the four possible configurations, i.e. the QDG-LGP-QDR configuration.

Table 1. Simulation conditions of the backlight components.

	LGP	DS	PS	Reflector
Dimensions (mm)	194 (Length)* 345 (Width)
Thickness (mm)	5 and 2	0.1	0.139	0.1
Material	PMMA^a	Air	3M Prism Layer Mat	PMMA
Optical property	Optical smoothing (Fresnel loss)	Top surface: Gaussian spawningOther surface: Optical smoothing (Fresnel loss)	Optical smoothing (Fresnel loss)	Top surface: Aluminum coating or Gaussian spawning
Pattern (mm)	Left surface: hape: prismX width: 0.05Y width: 4.99Height: 0.1Bottom surface:Shape: SphericalHeight: 0.05Radius: 0.05		Prism film (V):Height: 0.012X width:0.024Y width: 194Prism film(H):Height: 0.012X width:0.024Y width: 194

^aPoly(methyl methacrylate).

Table 2. Simulation conditions of QD films and LEDs.

Quantum Dot Films		LEDs
Dimensions (mm)	194 (Length)*345 (Width)	Amount	38
Thickness (mm)	0.04	Luminous Flux (lm)	5
Optical property	Optical smoothing (Fresnel loss)	Center wavelength (nm)	450 nm
MFP (mm)^a	Green: 0.02Red: 0.025

^aMean Free Path.

Figure 2. (Color online) Angular dependence of the luminance of two backlight units with QD films with (a) a specular reflector (Specular 1) and (b) a diffuse reflector (Diffuse 2). Four different configurations were used for each case.

Figure 3. (Color online) Comparison of the on-axis luminance values of all the cases, i.e. the backlights with five reflectors and four configurations (Specular 1: Windmöller & Hölscher, Specular 2: 3M, Diffuse 1: embossed-type, Diffuse 2: default film in the notebook, and Diffuse 3: adhesive-type).

Figure 4. (Color online) Angular dependence of the color coordinates of two backlight units with QD films with (a) a specular reflector (Specular 1) and (b) a diffuse reflector (Diffuse 2). Four different configurations were used for each case.

Table 3. Comparison of the average color coordinates and their standard deviations for the data shown in Figure 4.

	(x. y) Specular reflector	(x. y) Diffuse reflector
QDR-LGP-QDG	x: 0.281 ± 0.005y: 0.254 ± 0.007	x: 0.351 ± 0.005y: 0.267 ± 0.006
QDG-LGP-QDR	x: 0.324 ± 0.007y: 0.257 ± 0.006	x: 0.351 ± 0.008y: 0.283 ± 0.005
LGP-QDR-QDG	x: 0.352 ± 0.009y: 0.221 ± 0.007	x: 0.367 ± 0.009y: 0.226 ± 0.005
LGP-QDG-QDR	x: 0.308 ± 0.008y: 0.279 ± 0.009	x: 0.330 ± 0.008y: 0.276 ± 0.006

Figure 5. (Color online) Angular dependence of the luminance of two backlight units with QD films with (a) a specular reflector and (b) a diffuse reflector obtained from optical simulation at the same reflectance of 95%. Four different configurations were used for each case.

Figure 6. (Color online) (a) Dependence of the on-axis luminance on the reflectivity of the specular reflector in the backlight units with QD films obtained by simulation. (b) Comparison of the on-axis luminance values of the specular and diffuse reflectors for four configurations of backlight units with QD films obtained by simulation.