This PDF file contains the front matter associated with SPIE Proceedings Volume 8560, including the Title Page, Copyright information, Table of Contents, and Conference Committee listing.

Forensic light sources (FLS) have been used frequently in crime scene investigation as a scanning tool for crime scene evidence, such as gunpowder residue, semen, bloodstain, saliva and urine. There were several FLS reported in literature, such as Polilight®, Lumatec Superlite 400, PolirayTM, Bluemaxx BM500 and high intensity LED. LED-based light sources are low in cost and flexible in design. Moreover, LED technologies have been well developed recently, where several types of wavelength LED can be used for light source design. From literature, near-UV light (300-400nm) and blue (450nm) light are useful for detecting semen, urine and saliva stains, while 415nm light is useful for bloodstains detection. In this paper, a simple, low cost and portable LED-based multi-wavelength light source for forensic application is proposed. The proposed multi-wavelength light source is able to supply near-UV, blue and 415nm lights from the same point of source and direction, without utilizing any light guide, such as optical fiber. Each type of LED array was mounted separately on the different surfaces of a holder. DC motor was used to rotate the holder for directing the selected LED array to face the object. The proposed design is low in cost, easy to be manufactured, user-friendly and comparable to the other expensive FLS, such as Polilight® PL500 and Crime-lite®2, in terms of detectable dilution of bloodstains.

The double-side patterned sapphire structure was proposed to improve the light extraction efficiency (LEE) of flip-chip GaN-based light-emitting diodes (LEDs). The influences of sapphire substrate thickness, pattern shapes and sizes on LEE were analyzed by Monte Carlo simulation method. Using silicon oxide as mask membrane, double-side patterned sapphires were processed by the standard lithography and the reaction-ion-etching (RIE) technology. The LEDs with patterned sapphire were packaged. The measured light outputs of LEDs verified our predicted effects.

We propose a new and effective Light Guide Plate, called Empty Chamber Fresnel Lens Light Guide Plate (ECFL-LGP), to provide the merits of thin, lightweight, low-cost and high effect of light rays guiding for a medium or large LED-sourced Edge Lighting Backlight Module. It consists of a simple Empty Chamber and two sets of linear irregular Fresnel lenses. Due to the reasons that the structure of the Empty Chamber is simple and a Fresnel lens is thin and cheap, our ECFL-LGP will possess lower cost than the traditional hard LGP. On the other side, the irregular Fresnel lens in ECFL-LGP will be better than the traditional mesh-like dot about the effect of light rays guiding because its irregular linear groove angles can be evolved in terms of the optimization requirements of light rays guiding. As for the uniform problem of light rays guided to the LCD panel, we will design a double-deck linear irregular Fresnel lenses to act as a prismatic film according to the uniformity requirement. To overcome some problem caused by designing linear irregular Fresnel lenses, we propose an idea of dividing the designed Backlight Module into several sections to reduce the number of evolved groove angles, and dividing the design procedure into two stages: first, evolve two sets of linear irregular Fresnel lenses in the designed ECFL-LGP, then evolve four sets of linear irregular Fresnel lenses between the ECFL-LGP and the LCD panel. As a result, the thickness of the designed LED-sourced Edge Lighting Backlight Module will be 4.85 mm only (the LCD panel is not included).

Composed by thousands of microsphere-like structures on the surface, the plastic surface relief diffuser film with different transmittance and haze will be designed by optical simulation software. By using laser etching process, the molding will be fabricated on the self-developed equipment with nanosecond diode pumped solid state laser. Finally, the roll to roll UV curing process will be used for fabricating the diffuser film based on polycarbonate material. The relationship between the optical performance and the structure parameter and its distribution will be investigated. The optical performance of diffuser films will be tested by surface profiler, and spectrophotometer. These results will contribute to the design and production of customized diffuser films.

Raman spectra and infrared imaging systems are used for the study of internal temperatures of PLEDs. The aim is to investigate the thermal degradation of PLEDs with different current densities. Raman intensity is proportional to the number of molecules in the next higher vibration energy level, and accurate internal temperature of PLEDs at thermal equilibrium can be calculated with the ratio of anti-stokes to stokes Raman density by Boltzmann equation. With the current density of PLED going from 0 mA/cm² to 169 mA/cm²，it is found that the internal temperature of PLED increases accordingly. When the temperature comes to the glass transition temperature (T_g) of the emission layer, there is a phase change in it and the layer becomes free state as liquid, which is not stable. Local disfigurement in the emission layer results in short circuit between the cathode and the anode of a PLED, and the luminescence of PLED fails. Therefore, Raman spectrum is considered as a good method for detecting temperatures of thin-film semiconductor devices.

Laser speckle degrades image quality in laser displays. The speckle contrast needs to be correctly evaluated in designing laser displays. In this paper, a moving small diffuser for speckle reduction is set up for laser projection display system. We demonstrate the effect of the projection lens on speckle contrast under the scenarios of free-space and image geometry measurement with different configurations. The results show the speckle contrast in free-space geometry is measured as about 74.16% without projection lens and 60.74% with projection lens for the static diffuser, which are reduced to 2.75% when the diffuser moves for both with and without projection lens. In the imaging geometry, the moving diffuser reduces the speckle contrast from 83.22% to 9.61% without projection lens, and from 98.7% to 36.59% with projection lens.

The deflection of light of a single optical surface is limited by the Fresnel reflection loss and it is usually not enough to meet the requirements in large road width, tilt lighting LED lens design. This paper presents a method which greatly increases the light deflection angle of LED lens by combining a tilting aspherical surface with a freeform surface. Using this design method, a road lighting LED lens for length L= 30m, road width W=12m and tilt angle θ = 15 ° is designed and manufactured. The experimental results show that the overall road luminance uniformity is as high as 0.7. This design method greatly expand the light distributing capacity of the free-form surface LED lens, and it can be widely used in the design of LED road lighting lens and other illumination applications where large light deflection angle is needed.

Photoluminescence investigation of Eu activated Mg-substituted tricalcium phosphate (β-TCMP) phosphors were prepared by solid-state reaction. The structure and emission spectra were well characterized by X-ray diffraction (XRD) and photoluminescence (PL) techniques. The excitation and emission spectra show that all the Eu³⁺ doped β-TCMP samples can effectively emit the light excited by UV light. The red-emitting β-TCMP:Eu³⁺ phosphors may be efficient photoluminescent materials for solid-state lighting phosphors.

Europium doping barium thioaluminates thin films are sputtered by Al complex target embedded with BaS:Eu pellets sintered by spark plasma sintering (SPS). Thin films are deposited by RF-sputtering with complex target. BaAl₂S₄ is found in each thin film sample while BaAl₄S₇ appears in the samples only if the amount of BaS:Eu pellets is more than 3. Oxidizing products are BaAl₂O_4, BaSO₄ and Al₂O₃. The amounts of barium thioaluminates including BaAl₂S₄ and BaAl₄S₇ will increase while the one of Al₂O₃ and BaS decrease if more BaS:Eu pellets are embedded in the target during sputtering. Elements analysis is carried out by EDS. The Al/Ba ratio in thin films will approach 2.0 with more pellets existing in target. PL spectra of thin films are measured and analyzed. The most obvious emission peak in each spectrum is located at about 470nm which corresponds to the 4f⁶5d¹→4f⁷ transition of Eu2+ in BaAl₂S₄ lattice. The emission peak will approach 470nm as more pellets are embedded in complex target. As a result, it can be concluded that increasing the amounts of BaS:Eu pellets in complex target is an efficient way to achieve better Eu doping barium thioaluminates thin film.

According to the properties and distribution of Macadam ellipses on the CIE1931 (x, y), a new uniform chromaticity diagram named (U, C) obtained by using the coordinate translation and non-linear compression along radius direction with the aid of the iterative algorithm. Compared with CIE 1931 (x, y), the uniformity of (U, C) is obviously improved. Moreover, it appears to perform as well as or better than these chromaticity diagrams in the IPT and CIECAM02-UCS color spaces.

The variation laws of mutual coherence function in laser projector with moving diffuser for speckle reduction are studied based on the partly coherent theory. We take the magnification of lens and its spread function into consideration, it gives us a method to weigh the speckle reduction and the loss of optical energy while using the moving diffuser for speckle reduction, and it points out the selection of diffuser slice for laser display.

Quantum efficiency measurement of luminescence glasses for high-power white LED was investigated. Luminescence glasses have transparent and anisotropic characteristics, for this reason, we adopted an integrating sphere with 20cm diameter which was connected to a CCD spectrometer to obtain fluorescence spectra of the sample. The relative spectral intensity distribution of the sample under the light source excited was derived from the measured spectra firstly, then using the standard halogen lamp to calibrate the system, we got the absolute spectral intensity distribution, finally the quantum efficiency of the sample can be calculated based on the distribution. It provides an accurate method to measure the luminescence materials’ emission characters.