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With the development of holography and nanomanufacturing technology, metasurfaces are playing an increasingly important role in the field of holography. We designed a silicon cylindrical structure based on the Huygens metasurface. By exciting the Mie electric dipole and magnetic dipole resonance of the silicon cylindrical structure, a high transmission efficiency of 84% can be achieved at a wavelength of 633 nm, and a full phase coverage of 0-2π can be obtained by adjusting the radius of the silicon cylindrical. We used the angular spectrum algorithm to obtain the phase distribution relationship between the object image and the metasurface, and designed the arrangement of the silicon cylinder metasurface. The simulation obtained a high-fidelity hologram, and the structure has a high transmission efficiency around the 633 nm spectrum. This method can realize metasurface holography with high transmission efficiency, and it can be applied in holographic imaging.

We propose a full-color see-through three-dimensional (3D) display method based on volume holography. This method is based on real object interference, avoiding the device limitation of spatial light modulator (SLM). The volume holography has a slim and compact structure, which realizes 3D display through one single layer of photopolymer. We analyzed the recording mechanism of volume holographic gratings, diffraction characteristics, and influencing factors of refractive index modulation through Kogelnik’s coupled-wave theory and the monomer diffusion model of photopolymer. We built a multiplexing full-color reflective volume holographic recording optical system and conducted simultaneous exposure experiment. Under the illumination of white light, full-color 3D image can be reconstructed. Experimental results show that the average diffraction efficiency is about 53%, and the grating fringe pitch is less than 0.3 μm. The reconstructed image of volume holography has high diffraction efficiency, high resolution, strong stereo perception, and large observing angle, which provides a technical reference for augmented reality.

This paper developed light-emitting diode (LED) and laser models suitable for the design of uniform surface irradiation systems that use computer algorithms. During the evaluation factor for a two-dimensional particle swarm algorithm, the effects of energy utilization and uniformity were comprehensively considered and LED and laser models were given. The optimal design method was used with a laser and LED hybrid light source. According to the lighting requirements of lettuce, three types of lighting were simulated for the LED and laser models, and the best simulation results were selected for experiments. The experiment verified the feasibility of the above method and obtained a laser and LED hybrid lighting system with an energy utilization rate of about 78% and a uniformity of up to 85%.

In order to improve the effect, clarity and resolution of anti-counterfeiting, this paper proposes a method of reflection volume holographic three-dimensional (3D) anti-counterfeiting. This method adopts reflection volume holographic interference recording of 3D object to achieve 3D anti-counterfeiting. The principle of reflection volume holography was analyzed by using Kogelnik’s coupled wave theory. A reflection volume holographic anti-counterfeiting recording optical path based on a monochromatic laser was constructed. Photopolymer is used as the volume holographic recording material, and a metal school badge is used as the object. Experimental results show that the reflection holographic gratings can record and reproduce 3D object, and the 3D shape of the reproduced image is consistent with the object, which improves the effect of anti-counterfeiting.

The large field of view projection system based on the principle of diffraction has a simple optical system, but it often consumes a lot of time when calculating the hologram using the traditional iterative algorithm, which limits the application range of the system. In this paper, we use deep learning to accelerate the calculation of holograms, and experiment results proves that the holograms calculated by U-net have good performance.

Volume holograms can achieve concentration of sunlight, but it has shortcomings such as small concentration angle, dispersion, and complex production process of the volume holography material, which is difficult to mass produce. This paper proposes a method based on the metasurface concentrating sunlight. We analyzed the mechanism of volume holographic light focusing by Kogelnik coupling wave theory, which is greatly limited by wavelength selectivity. Utilizing the metasurface control mechanism on the wave front phase, the array arrangement that meets the light concentrating effect was designed. Simulation analysis shows that the metasurface can achieve light concentration in the visible light band with low dispersion.

Volume holograms can record and reproduce three-dimensional object. Compared with planar holograms, volume holograms can improve the resolution, stereo perception and realism of anti-counterfeiting, and realize three-dimensional anti-counterfeiting. In order to improve the diffraction efficiency and anti-counterfeiting effect of volume holographic anti-counterfeiting, this paper proposes a reflection volume holographic three-dimensional anti-counterfeiting method based on photopolymer. The diffraction characteristics and influencing factors are analyzed by Kogelnik’s coupled wave theory. Based on Piazzolla’s monomer diffusion model, the effects of exposure energy and exposure intensity on refractive index modulation and diffraction efficiency were studied. The simulation results show that the reflection volume holograms can achieve a greater refractive index modulation, with higher diffraction efficiency, stronger wavelength selectivity, which enhances the effect of three-dimensional anti-counterfeiting.

Compressive sensing (CS) is employed in holographic imaging for multilayer imaging. We show tomography of a continuous sample by introducing a microscope objective (MO) in an in-line compressive holographic system, and analyze the reasons why applying compressive holographic microscopy can achieve tomography of continuous samples.

A fast computer-generated hologram (CGH) generation method for three-dimensional point cloud models is proposed. The points of the model are classified into parallel two-dimensional layers after a layer spacing δz is set. Then, the CGH can be calculated by a layer-based method. In addition, a simple approach for occlusion culling is introduced. The computation time is reduced by thousands of times compared to point-based method. Discussion results show that the proposed method is more effective for larger models, and for models with huge number of points, the computation efficiency can be further enhanced by choosing larger layer spacing and optimized classification method. The proposed method will be an ideal CGH generation method for point cloud models, extremely suitable for real-time holographic reconstruction of the real scene.

Autostereoscopic displays employing lenticular sheets have broad applications due to the high transmittance of lenticular sheet. However, due to the restriction of lens array design and processing, the imperfect image of lenses can reduce the quality experience of autostereoscopic displays. Stereo depth is one of the qualities of experience parameters, which relates to the three-dimensional effect. Therefore, to quantize the reduction effect of stereo depth caused by lens aberration is of great value. In this paper, we implement a binocular model of an autostereoscopic display system with lens array to analyze this effect, which is different from the previously used monocular model. Two receivers in the positions of viewer&rsquo, s eyes are set on the viewing plane, and a similar factor is defined to evaluate the difference of light spots perceived by the two receivers. When the similar factor exceeds a certain value, the two spots cannot be fused in the brain, thus restricting the perceived stereo depth. Both in simulation and experiment, a sudden decrease of the similar factor is observed when the viewing angle exceeds 16&deg, In the subjective experiment, all the sixteen viewers feel a sudden decrease of stereo depth when the viewing angle exceeds 16&deg, which further verifies the validity of the model. The model and the method are significant for improving the viewing experience of autostereoscopic displays and providing a guidance on autostereoscopic display system designing.

The three-dimensional (3D) reconstruction of spatially continuous objects in compressive holography (CH) is difficult owing to the large axial interval. Hence, in this work we propose an algorithm for staggered tomography based on CH (ST-CH) that performs multiple staggered compressive sensing reconstructions to obtain a supersaturated reconstructed object field with a small axial interval. ST-CH is found to improve positioning accuracy by approximately one order of magnitude compared with conventional CH method. The moving postures and behaviors of Caenorhabditis elegans were observed experimentally in 3D space. Segmented positioning was applied along the skeleton of a continuous object to position different object parts; finally, observation of a kinematic fiber was achieved.

An optical encryption method based on computer generated holograms printing of photopolymer is presented. Fraunhofer diffraction is performed based on the Gerchberg-Saxton algorithm, and a hologram of the Advanced Encryption Standard encrypted Quick Response code is generated to record the ciphertext. The holograms of the key and the three-dimensional image are generated by the angular spectrum diffraction algorithm. The experimental results show that large-size encrypted Quick Response (QR) code and miniature keys can be printed in photopolymers, which has good application prospects in optical encryption. This method has the advantages of high-density storage, high speed, large fault tolerance, and anti-peeping.

Emerging technologies, such as smart wearable devices, augmented reality (AR)/virtual reality (VR) displays, and naked-eye 3D projection, have gradually entered our lives, accompanied by an urgent market demand for high-end display technologies. Ultra-high-resolution displays, flexible displays, and transparent displays are all important types of future display technology, and traditional display technology cannot meet the relevant requirements. Micro-light-emitting diodes (micro-LEDs), which have the advantages of a high contrast, a short response time, a wide color gamut, low power consumption, and a long life, are expected to replace traditional liquid-crystal displays (LCD) and organic light-emitting diodes (OLED) screens and become the leaders in the next generation of display technology. However, there are two major obstacles to moving micro-LEDs from the laboratory to the commercial market. One is improving the yield rate and reducing the cost of the mass transfer of micro-LEDs, and the other is realizing a full-color display using micro-LED chips. This review will outline the three main methods for applying current micro-LED full-color displays, red, green, and blue (RGB) three-color micro-LED transfer technology, color conversion technology, and single-chip multi-color growth technology, to summarize present-day micro-LED full-color display technologies and help guide the follow-up research.

A new double-layer sunlight concentration system, where each layer is divided into two regions, is proposed, and the system has four volume holograms. Since the four holograms convert light in different directions, the interlayer crosstalk is reduced, and the system has a high concentration ratio. The simulation results show that the concentration system can achieve a 30° operation angle range. The holograms are fabricated on photopolymer substrates, and the left half of the system is implemented using two holograms. The characteristics of the left half of the system are assessed. The agreement of the simulation and experimental results on diffraction efficiency validates the proposed method. The tested monochromatic concentration ratio can achieve a record of 418.8, and the concentration ratio under sunlight is 5.38. The experiment results of light use efficiency are close to the simulation with non-crosstalk, which indicates that the interlayer crosstalk is small.

In this paper, we propose a novel non-iterative approach based on the two-dimensional discrete wavelet transform (DWT) for generating binary holograms in in-line holography. This method is able to alleviate the degradation appearance on the reconstructed image caused by the direct sign-thresholding. Numerical experiments of this method are given in this paper. It is shown that high-quality images of the binary hologram can be reconstructed by using the proposed method. Additionally, the reconstructed images also contain less amount of noise contamination.

The layer-based method for three-dimensional (3D) hologram generation suffers from reconstruction quality decreasing. On the basis of the layer-based method, a new method based on the idea of “space-division” is proposed. The method divides the object into small pieces, named spaces; for spaces with small number of points, the point-based method is used for hologram generation, to ensure the reconstruction quality; for spaces with large number of points, the fast Fourier transform method is used to ensure the computation efficiency. An index named “quality-time ratio” Q is defined, to synthetically evaluate the influence effect of the number of portions, the number of layers and the number of points to the effect of the algorithm. The simulation results show that, the increment of the number of portions improves Q the most effectively, which proves the validity of our method. The method is further tested by computer and optical reconstructions using different objects, and it is proved that the space partitioning method can obtain reconstructed images with the same quality in about 30% fewer time.

We combine the 3D hybrid-Weickert nonlinear diffusion regularizer with digital holography, which can distinguish the locations of certain small-sized particles that are overlapped along the z-axis, to realize autofocusing of multiple micro-objects and simultaneously remove the defocused images. The proposed method is applied to all the reconstruction slices generated from the hologram after each back-propagation. After applying the proposed scheme for certain small-sized particles, the reconstructed image at the ground truth z position is retained, the defocused images are diffused out when the reconstruction range along the z-axis is sufficiently long and the reconstruction depth spacing is sufficiently fine. The results demonstrated that the proposed scheme can diffuse out the defocused images that are 20 μm from the ground truth z position, despite several scattering particles of different diameters being completely overlapped along the z-axis with a distance of 800 μm when the hologram pixel pitch is 2 μm. In addition, the results revealed that the sparsity distribution of the ground truth z slice is not affected by the sparsity distribution of the corresponding defocused images when the diameter of the particle is less than 35 μm and the reconstruction depth spacing is more than 20 μm.

A method to improve the radial resolution using special structured light is proposed in the field of digital holographic microscopy (DHM). A specimen is illuminated with circular symmetrical structured light that makes the spectrum have radial movement, so that high frequency components of the specimen are moved into the passband of the receiver to overcome the diffraction limit. In the DHM imaging system, Computer Generated Hologram (CGH) technology is used to generate the required structured light grating. Then the grating is loaded into a spatial light modulator (SLM) to obtain specific structured illumination. After recording the hologram, digital reconstruction, for the microstructure of a binary optical element that needs to observe radial distribution, the radial resolution of the specimen is improved experimentally compare it with the result of one-dimensional sinusoidal structured light imaging. And a method of designing structured light is presented.

A prototype autostereoscopic three-dimensional (3D) light-emitting diode (LED) display using a cylindrical diffractive optical elements (C-DOEs) sheet as the optical steering element is proposed. The operation of the system and the calculation method of the system parameters are described in detail. The DOEs sheet is placed from a distance from the LED display panel which is five times smaller of the existing technology, and the column spacings of the pixels of the LED display panel are nonequal in order to equalize the distance between the viewing zones. The prototype has a 1.33 m $^2$ display panel, 384 $\times$ 144 resolution and a horizontal field of view of 60 $^{\circ}$ . The experimental result shows that the proposed method is a potential autostereoscopic technology for the large area LED displays.

Hydrogen sulfide poisoning is a common occupational hazard, whose mortality and incidence rates are first and second, respectively, among occupational poisoning incidents in China. The main target organs of its toxicity are in the central nervous system and respiratory system. However, there are currently no specific direct tests that can be used to diagnose poisoned patients. In this study, we developed a serum metabonomic method using orthogonal partial least squares-discriminate analysis (OPLS-DA), based on gas chromatography-mass spectrometry (GC/MS) to evaluate the effect of chronic poisoning by hydrogen sulfide in rats. The OPLS-DA data demonstrated that the model group (n = 60) differed significantly from the control group (n = 30), suggesting that the metabolic profiles of the two groups are markedly different. Alterations in the levels of some metabolites such as citrate, galactose, lactate, mannose, inositol, urea, phosphate, alanine and valine were detected by OPLS-DA analysis. We observed changes in metabolic pathways including lipid metabolism, energy metabolism and amino metabolism in the model group. Our results indicate that GC/MS-based metabonomic methods may provide novel detection means for chronic hydrogen sulfide poisoning.

During the design process of Blu-ray disc optical pick-up (BD OPU), the optical system and the collimator lens design is especially important. This paper designs an optical system and some lenses for the BD OPU, including collimator lens, beam shaping lens for laser beam shaping, and cylinder lens for signal detecting. In this OPU, we use a triplet lens to collimate the laser beam. At the same time, we build a series of assembly jigs to make sure that each lens can be put into the OPU basement properly. At last, we get the reading spot image and S-curve photo of OPU, which can be used to read Blu-ray disc (BD).

This paper introduces a compact optical information storage sensing system. Applications of this system include longitudinal surface plasmon resonance detection of gold nanorods with a single femtosecond laser in three-dimensional space as well as data storage. A diffractive optical element (DOE) is applied in the system to separate the recording-reading beam from the servo beam. This allows us to apply a single laser and one objective lens in a single optical path for the servo beam and the recording-reading beam. The optical system has a linear region of 8 λ, which is compatible with current DVD servo modules. The wavefront error of the optical system is below 0.03 λ(rms). The minimum grating period of the DOE is 13.4 µm, and the depth of the DOE is 1.2 µm, which makes fabrication of it possible. The DOE is also designed to conveniently control the layer-selection process, as there is a linear correlation between the displacement of the DOE and the layer-selection distance. The displacement of DOE is in the range of 0-6.045 mm when the thickness of the layer-selection is 0.3 mm. Experiments were performed and the results have been verified.

A hologram always contains redundancy. Its huge information content brings difficulties in the storage and transmission. In addition, when a computer-generated hologram (CGH) is reproduced, the zero-order diffraction spot which occupies most of energy reduces the contrast of reproduced image and disturbs the observation and recording. In this paper, discrete cosine transform (DCT) is used to compress the information content of a CGH and to eliminate the zero-order spot. Numerical simulation results showed that, DCT could effectively remove about 64.8% of the redundancy without affecting the quality of reconstruction. It also eliminated the zero-order spot and improved the contrast of reproduced image. Finally, the optical reconstruction results were shown. Numerical and optical experiments both proved that, the reconstructed image after compression almost did not lose any resolution that human eyes could perceive.

The three-dimensional(3D) displays based on binocular parallax have drawn increasingly interests. The light splitting element, which presents separate images to the viewer’s left and right eyes, plays an important part in the auto-stereoscopic display. Lenticular lenses are widely used as the light splitting elements. However, the crosstalk resulted from the unsatisfied splitting may reduce the 3D experience. It was determined that the most suitable cross sectional shape for lenticular lenses is elliptical. Firstly, the formula of the surface is derived based on the ellipse expression and the requirement of the 3D display system, that is y 2 +0.5651x 2 − 303.4768=0. Secondly, one axial source and 4 off-axial sources placed at the heights of 2.5 mm , 5 mm , 7.5 mm and 8 mm are used to analyze the beam splitting quality of the cylindrical and elliptical lens element, respectively. The spot of elliptical lens is smaller which means a better beam splitting quality. Thirdly, Monte Carlo Non-Sequential Ray tracing algorithm is used to simulate the luminance distribution on the viewing plane, the narrower width of vertical stripes means that the aberration is suppressed. Finally, the shape of elliptical can reduce the processing difficulty with the 10μm minimum step width. In a word, the optimization of the surface has a significant effect on the improvement of stereoscopic depth and the reduction of ghost images.

Digital Micro-mirror Device (DMD) is an important tool in holographic display owning high-speed refresh rate and good diffraction efficiency. However, the reconstruction light source has great impact to image quality. A new holographic display system based on DMD for using light-emitting diodes (LEDs), is proposed in this paper. LEDs are chosen as light source to replace the laser, since it can reduce the speckle noise effectively, which is caused by both temporal and spatial coherence of laser. In order to solve the problem using LED as DMD holographic display light source, the characteristics of DMD as the display device for holographic displays are studied. An aspheric collimator for LED is used to improve the optical efficiency. A spatial filter is used to improve the coherence. The experimental results show that this lighting system has a good display quality.

A color LED holographic display system based on DMD is proposed in this paper. Ideal display effects can be obtained by using this system.

An LED illumination system employing freeform lens for holographic display is proposed. The design of the freeform lens is based on aplanatic principle. The illumination system has the advantages of good coherence, collimation and uniformity.

Large-size autostereoscopic 3D LED displays are commonly used in outdoor or large indoor space, and have the properties of long viewing distance and relatively low light intensity at the viewing distance. The instruments used to measure the characteristics (crosstalk, inconsistency, chromatic dispersion, etc.) of the displays should have long working distance and high sensitivity. In this paper, we propose a methodology for characteristics measurement based on a distribution photometer with a working distance of 5.76m and the illumination sensitivity of 0.001 mlx. A display panel holder is fabricated and attached on the turning stage of the distribution photometer. Specific test images are loaded on the display separately, and the luminance data at the distance of 5.76m to the panel are measured. Then the data are transformed into the light intensity at the optimum viewing distance. According to definitions of the characteristics of the 3D displays, the crosstalk, inconsistency, chromatic dispersion could be calculated. The test results and analysis of the characteristics of an autostereoscopic 3D LED display are proposed.

A lens actuator is an important mechanical–electrical component in optical pickup. For the high-sensitivity actuator used in a super-multi recorder, a novel magnetic circuit is proposed in this paper. This magnetic circuit consists of six thick permanent magnets with regulated placement, two thin permanent magnets, a base yoke, and an upper yoke. Experimental results verified the feasibility of the designed magnetic circuit.

Interactive technologies have been greatly developed in recent years, especially in projection field. However, at present, most interactive projection systems are based on special designed interactive pens or whiteboards, which is inconvenient and limits the improvement of user experience. In this paper, we introduced our recent progress on theoretically modeling a real-time interactive projection system. The system permits the user to easily operate or draw on the projection screen directly by fingers without any other auxiliary equipment. The projector projects infrared striping patterns onto the screen and the CCD captures the deformational image. We resolve the finger’s position and track its movement by processing the deformational image in real-time. A new way to determine whether the finger touches the screen is proposed. The first deformational fringe on the fingertip and the first fringe at the finger shadow are the same one. The correspondence is obtained, so the location parameters can be decided by triangulation. The simulation results are given, and errors are analyzed.

In this paper, Computational fluid dynamics (CFD) analysis and design of experiment (DOE) are employed to optimize the thermal performance of LED in micro projector. First, an original micro-projector is simulated using Flotherm which shows that the junction temperature of LED exceeds the temperature limit. Secondly, a solution redesigning the air duct and reducing the effect of flow bypass and fan hub on the performance of heat sink lowers the junction temperature by 8°C. At last, DOE is applied to find the optimal setting of the design parameters for the heat sink, which reduced the LED junction temperature by 13°C. In addition, a test has been presented and the result demonstrates that the error is less than 10%.

With the development of wireless sensor networks, low-cost and high-reliability industrial wireless sensor networks become feasible. The industrial wireless sensor networks should be designed to resist the failure of some nodes in harsh environments. In order to minimize the installation cost of relay nodes for fault tolerant hierarchical networks planning, we proposed a genetic simulated annealing hybrid algorithm. The algorithm determines the number of relay nodes, along with their locations, so that each sensor node can be covered by at least two relay nodes, and the network of relay nodes is 2-connected. The result produced by the presented algorithm within limited number of iterations is reasonable and the algorithm leads to improvements compared with genetic algorithm and integer linear program (ILP).

Mini-projectors based on LED illumination have already become a hotspot of projector industry, and time-sequential stereoscopic mini-projector has been developed. However, viewers to this type of 3D projector usually suffered from dark and flickering images caused by false synchronization of images and glasses, and the low transmittance of LC glasses. We propose a new type of polarized mini-3D-projector, which employs double LED illumination engines, and double LCoS panels. The optical model of the optical engine for the mini-3D-projector is built based on the measured optical qualities of the key optical elements. The large divergence angle is the main factor which affects disparity according to the simulated analysis. The first version of prototype is developed, which has low disparity (

CBHD (China Blue High Definition Disc) is a high-definition optical disc standard with Chinese independent intellectual property. Compared with DVD optical pick-up, CBHD optical pick-up, key component of CBHD player, has significant improvement in the channel bit rate and certain reduction in acceptable tolerance range for disk tilt, etc. This paper specifies the servo control system construction for the CBHD radial tracing and axial tracking. This servo control system should ensure the optical beam of OPU focusing on the Disc plane and following the track of CBHD channel accurately. According to the expected radial/axial maximum acceleration and the limitation of emax, an open-loop transfer function specifying the servo system for axial and radial tracking is introduced. The corresponding servo control algorithm including IIR filter based on the above-mentioned transfer function is theoretically analyzed and numerically simulated by MATLAB. Because optical pick-ups are different in dynamic properties and its digital circuit exist quantization error, time delay nonlinearity, etc, the tuning of IIR parameters is laborious and time-consuming. Thus a experimental platform for CBHD optical pick-up servo system are designed in this paper, and an user-friendly interface for IIR parameters adjustment is given. Experimental results showed that this control system has good servo characteristics in time-domain and frequency-domain.

The optical pickup unit is a kind of mass-produced product as well as a diffraction-limited micro-optical system. Thus the optical elements are assembled serially in the production line, and its fabricating and assembling errors should be controlled to achieve a diffraction-limited focus spot on the disk. And the reflected light from the disk on the photo detector would be converted and processed in the servo control system and evaluated using the electrical evaluator. Thus a correlation between the electrical evaluator and the spot intensity should be considered when setting the testing standard for a production line. In this paper, the optical pickup is measured using a spot analyzing system. Its electrical signals are described in the evaluator. The optical system in the optical pickup would be divided into two testing parts: base part and focusing part. The base part includes the laser diode, collimator, prism, quarter-wave-plate, beam splitter and reflective mirror; while the focusing part has objective lens, phase plate, wave-plate, and so on. The focus quality is measured using the spot analyzer. Then these optical pickups are processed to get the electrical signals directly from the evaluator. Finally the parameters achieved using these two systems are compared and its correlation are investigated. This method is verified when designing a DVD production line and might be useful in establishing the standards for a new optical pickup.

The design of a binocular visual system with long eye relief using the freeform profile is investigated in this paper. The surface parameters of the original profile were calculated upon its geometrical structure specification, and the tangential profile of the surface is described using the sample points. The astigmatism along the tangential plane can meet the system requirement.

The design of a binocular visual system of long eye relief using a freeform profile is investigated in this paper. It provides a virtual enlarged image and is used for early diagnosis of eye problem.

The design of a visual optical system for eye and vision examination using video-based chart is investigated in this paper. It produced a virtual image larger than the original display and much farther away from the tester eye. The diagonal length of a virtual image is enlarged as the optical system is designed to match the resolution of human eye. The optical system provides a wide observing area. The optical system also has a large field of view. It has a comfortable long eye relief. The design results and image analysis are also discussed in this paper.

During the design process of Blu-ray Disc Optical Pick-Up (BD OPU), the optical system design plays a significant role, and the collimator lens design is especially important. According to the PW optical design formulas, this paper calculates the initial parameters of collimator lens. It chooses the triplet type collimator lens instead of aspheric lens to design in order to reduce the manufacture difficulty according to the real situation in China. And then based on the initial parameters of collimator lens, the paper optimizes the triplet collimator lens to reach a good quality effect of parallel beam. At last it puts these design data into manufacture and adjusts the distance between the LD and the collimator lens by using the sleeve mechanism structure to see the real effect of collimating. Finally the assembly experiment of whole BD OPU validates these design that it can be used in BD OPU very well.

The NVD(Next generation Versatile Disc) OPU(Optical Pick-Up), based on general red light, is able to read a new type of disk which has 15 GB capacity with 2 layers on one side. The linear span of the focus error signal of original NVD OPU light path is shorter than the requirement proposed by the electron servo system. Increasing the thickness of the tilted-parallel-plate to broaden the linear span will increase the coma aberration which will deteriorate the servo accuracy. Furthermore, the thickness of the tilted-parallel-plate is related to the coexistence of DVD and CD servo signal. Therefore, an aberration-compensated and multi-freedom servo lens for NVD OPU is necessary. The servo lens proposed in this paper is a single lens, which the first surface is a combination of cylindrical surface and tilted surface, and the rear surface is a common spherical surface. According to the conversion of Zernike-to-Seidel wavefront aberration, a given amount of astigmatism will be achieved by bending the curvature of the cylindrical surface to broaden the linear span, and the coma will be corrected by the tilted surface. The function of the spherical surface is guaranteeing the coexistence of DVD and CD servo signal. Finally, the specification of the servo lens and simulation result of the whole system will be addressed.

The collimator in BD/DVD/CD compatible optical pickup unit has been designed to motivate and translate along the optical axis by the motor, for multi kinds of disc compatibilities of spherical aberration compensation incurred when reading and writing. The driving motor is huge and not easy to activate. Another technical obstacle to be handled is the alignment so that the reflective mirror should be adjusted and rotated along two axes. In this paper, this kind of optical pickup unit might be minimized, and realize dynamic focus control by micro machined deformable mirror. The optimal sensitivity should be achieved when the focusing spot size is equal to the diffraction limited diameter of the focal spot of the reflected beam.

This paper deals with the actuator movement measurement for objective lens actuator in optical pickup. An optical pickup is an optical apparatus to record and/or reproduce information from an optical disc, and move in a radial direction on the optical disc. The objective lens actuator helps move an objective lens in a tracking direction, a focusing direction, and/or a tilting direction, spot the laser beam on a correct portion of the optical disc. It basically carries out tracking and focusing movements, i.e., a biaxial movement. For high recording density media, the optical pickup actuator requires a triaxial or quadriaxial movement including a tilting movement in addition to the existing biaxial movement. For information recording and/or reproducing correctly, the movement range of the actuator should be proper to accurately follow the disc deviation. Alternative methods of movement measurement have been proposed. One method employed now uses a plane plate reflecting laser beam which describes the movement. It requires two laser devices for tracking direction and the focusing direction measurement respectively. Here we propose a method for describing the tracking and focusing movements on one laser device. In this method an external cone is used, with the same weight as the objective lens. It could reflect laser beam back to the linear CCD. The diameter of the external cone base is equal to that of the objective, which is crucial for a stable placement. The ratio of height to width of the external cone is designed and optimized, so that to satisfy the accuracy of the movement measurement and minimize the device. Measurement with this method has proved satisfactory for certain CD/DVD optical pickup.

This paper deals with the measurement of aspherics on surfaces of microscope condenser in mass production. The aspheric surface in microscope condenser is a kind of optical surface working under very large numerical aperture and small field of view. To fulfill Kohler illumination for the microscope condenser, the aspheric surface must be fabricated as well as designed capable of projecting an image of the source, large enough to fill the sub stage condenser of the microscope. For larger numerical aperture condenser fabrication, it is crucial to guarantee a reasonable aspheric profile for spherical aberration compensation and even illumination. Here we established the equipment for microscope condenser aspheric profile measuring in mass production. The industry microscope is reconstructed to image the profile, with LED panel light source for even backlighting. The profile, captured with a high resolution CCD, is processed. It can be compared with theoretic aspheric profile directly or interpolated with a predefined polynomial. In this method, supports for aspheric lens fabrication and measurement are designed and employed on the industry microscope. It guaranteed that a table of points can accurately describe the profile of the aspheric surface, introducing less assembling error. Measurement with this method has proved satisfactory for certain high aperture microscope condenser at low cost. For systems requiring still higher accuracy, the CCD resolution may have to be increased and interpolation method optimized accordingly but the online aspheric testing equipment with proper supports could surely improve the accuracy of aspheric surface fabrication at low cost.

In Blu-ray Disc Optical Pick-up, the collimating and beam shaping play a significant role for laser beam process. So this paper firstly gives out a collimating and beam shaping system according to China manufacture situation. And then based on Laser Optics and Fourier Optics, this paper improves the calculation method of energy coupling efficiency for collimator lens. At last, it builds a simple Interference Instrument which is used for adjusting the collimator lens and beam shaper. This apparatus is built based on the theory of interference theory. The simplest example of an electromagnetic wave is the plane wave. The plane wave is produced by a monochromatic point source at infinity and is approximated by a collimated light source. Here the paper uses this Interference Instrument to assemble the collimator lens with laser diode and check the quality of the beam shaping. Meanwhile this collimating and beam shaping system can be produced easily in China, as it is suitable for Chinese optical element manufacture skill lever and can be precise assembled by using simple instruments. So it will make that producing BD OPU in China with a lower cost comes true.

Based on the focus pre-search a method is presented to measure the characters of the traverse focus error detection system. In the pre-search of traverse focus servo system, the traverse focus offset is measured by the focus error occurring time, and the traverse focus error sensitivity and linear range are measured by the focus error slope and peak-to-peak value. A traverse focus error detection system is measured. The results show that the traverse focus offset is too high to stable the focus servo.

As the executive part, the actuator of optical pick-up (OPU) accomplishes the servo action actually. The dynamic characteristics of the OPU actuator determine the precision of focusing and tracking servo system, so it will influence the reading performance of optical pick-up. As the density of optical storage increases, the OPU actuator has a high servo bandwidth for its focusing and tracking control to follow dynamic disturbances by high density and high rotational speed of disk. The dynamic response curve should be as smooth as possible in its linear area. In this paper, the influence of the rolling of moving part on the actuator's dynamic characteristics is studied. Because of some design reasons, the moving part of the actuator may roll in three dimensions during the working status. It's one of the most important factors to influence the dynamic characteristics of actuator. Firstly, the reason of rolling and the influence on dynamic characteristics are studied. In the design of actuator we should pay attention to three important points, which are the gravitational point, the equivalent driving force point and the equivalent sustained point. When the three points are not accordant during the moving action, the rolling occurs. The dynamic response curve will have some unexpected resonances at certain frequency area. This phenomenon is analyzed by kinetic method. Secondly, a model of the actuator is founded referring to an actual type of actuator. By finite element analysis software (ANSYS), the mechanical and magnetic simulation is performed. The special distributing of electromagnetic field is described and the driving force is analyzed. Thirdly, the dynamic characteristics of some actuators with rolling are tested. The experimental result is consistent with the simulation result. So the validity of this study is verified. At last, the possible methods to avoid rolling of moving part are introduced.

It is well known that the optical pick-up (OPU) plays a very important role in optical storage system. And the quality of OPU can be measured by the characteristics of OPU read-out spot for high density optical storage. Therefore this paper mainly designs an OPU model for high density optical storage to study the characteristics of OPU read-out spot. Firstly it analyses the optical read-out principle in OPU and contrives an optical read-out system based on the hereinbefore theory. In this step it chiefly designs the grating, splitter, collimator lens and objective lens. Secondly based on the aberrations analysis and theory involved by the splitter, the collimator lens and the optical lens, the paper uses the software CODE V to calculate the aberrations and to optimize the optical read-out system. Then the author can receive an ideal OPU read-out spot for high density optical storage and obtain the characteristics of the ideal OPU read-out spot. At the same time this paper analyses some influence factors which can directly affect the characteristics of the OPU read-out spot. Thirdly according to the up data the author practically manufactures a real optical pick-up to validate the hereinbefore designed optical read-out system. And it uses the Optical Spot Analyzer to get the image of the read-out spot. Comparing the ideal image to the actual image of the designed optical read-out system, the author finds out that the upwards analyses and design is suitable for high density storage and can be used in the actual production. And the author also receives the conclusion that the mostly influences on characteristics of OPU read-out spot for high density optical storage factors is not only the process of designing the grating, splitter, collimator lens and objective lens, but also the assembling work precision

This paper principally analyses the influence of the DVD traverse manufacture and assembly error to the servo system, presents a specific servo system applied for DVD traverse tester, which is a digital servo based on general DSP. The repetitive control scheme is adopted to enhance the robustness to the periodic disturbance.

This paper presents a digital servo system using general digital signal processor (DSP) and gives the constitution of the servo system. The authors principally discuss the design method of digital servo algorithm. The repetitive control scheme is adopted to enhance the system performance to periodic disturbance.

The characteristic parameters of focusing and tracking servo systems have an important influence on the control accuracy. Among these parameters, those related to DVD optical pickups should be taken more account before designing servo control algorithm and Jitter is a key parameter to evaluate the comprehensive properties of DVD servo systems. This paper analyzes their influences on DVD servo system, discusses the evaluation and test methods of some key parameters according to actual testing results.