Site Visited: Hoya Corporation R&D Center
3-3-1, Musashino, Akishima-shi
Tokyo, 196 Japan
Date Visited: November 15, 1994

Report Author: S. Esener



S. Esener
D. Keck


S. Takahashi
Dr. Eng., General Manager
T. Yamashita
Optical Fiber Group Leader, Photonics Section
Y. Yokoo
Guided Wave Opt. Group Leader, Photonics Section
K. Matsumoto
Advanced Optical Devices Group Leader, Display Section
T. Miura
Advanced Optical Devices Group, Display Section
Dr. Y. Tomita
Analytical Chemistry Group Leader, Analytical Technology Section
S. Omi
Nonlinear Group Leader, Photonics Section
K. Satoh
Device Engineering Group, Photonics Section
H. Mitsui
Advanced Thin Film Group, Electronics Section


Since its establishment in 1941 as JapanÍs first specialty optical glass manufacturer, Hoya Corporation continues to diversify its operations in three business segments: Optics and Electronics, Health and Culture, and Software and Service, which supports the other two segments. Hoya has a global network of subsidiaries and affiliates anchored in Europe, North America, and Asia and Oceania. Hoya is a listed company with net sales of about 135 billion yen(($1.35 billion). It employs 7,741 people. Thirty percent of Hoya's gross sales are generated overseas.

Presently, Hoya's main income of 81 billion yen is generated by the Health and Culture business segment. This unit produces contact lenses and intraocular lenses (7.2 billion yen); eye glasses with high index and low dispersion (58.2 billion yen); and crystal glassware for the sophisticated end of the market (15.5 million yen).

The Optics and Electronics segment produces photomasks for IC fabrication, glass magnetic disks for PC hard drives, and liquid crystal displays for a wide spectrum of applications (25.7 billion yen). Hoya also produces lenses and lens blanks and nonspherical molded-glass lenses that allow less aberrations for still and video cameras, binocular lenses, and office automation equipment (23.5 billion yen).

Finally Hoya's third segment, Software and Services provides special software development and in-house services (4.3 billion yen). Hoya is also involved with international partners in developing complete solutions for communication networks. For example, a subsidiary, Hoya-Schott Corporation, combines Schott's silica fiber technology with HoyaÍs cold light sources and coupling technology

Under the guidance of its chairman Tetsuo Suzuki and its president Mamoru Yamanaka, Hoya is aiming to transition from being a glass company to a "total company" by exploring the possibilities offered by optoelectronics technology for the 21st century.


In April 1994, Hoya went through a reorganization of its corporate structure as part of its new medium-term management plan. This plan encourages process innovation through minimizing costs, shortening lead and manufacturing times, and streamlining the manufacturing process, accompanied by global advancement of its production and sales network, and a streamlined corporate organization that comprises only three levels.

This plan also requires the introduction of new products. With this objective in mind, the Hoya group is making a concerted effort to conduct product and technology R&D. As a consequence, the company's R&D effort has been consolidated into one R&D center by combining its Materials Research Laboratory and Device Development Center. The goal of this integrated R&D system is to encompass all stages of the R&D process, from materials development to the commercialization of new products. The links between the R&D Center and the development departments in all divisions have been strengthened, and although sales have declined, R&D funding has been protected. R&D expenditures comprise 5% of gross sales, with 2% spent at the R&D center and the remaining 3% in different divisions. About 80% of R&D expenditures were focused on optoelectronics at the time of the JTEC visit. The R&D center employs about 100 researchers; another 50 researchers are working in the divisions. Out of 150 researchers, it was estimated that 10% had PhDs, 40% had master's degrees, and the remaining 50% had bachelor's degrees.

Hoya R&D Center participates in Japanese government programs, especially in the area of nonlinear optics. The patents generated from such activities belong to the government, with the company receiving a nonexclusive license. Hoya was involved in the development of electroluminescent organic materials for display applications, but this effort has been completely stopped because it was not as successful as LCD technology. Hoya collaborates with the Tokyo Institute of Technology on materials characterization.


IR Transmitting Fluoride Glass Fiber

For applications including laser power delivery, optical temperature monitoring, thermal image transmission and spectroscopy, repeaterless telecommunications, and the development of fiber lasers and amplifiers, Hoya R&D center is conducting basic fundamental research in fluoride glass fibers under T. Yamashita. The center's effort is mostly concentrated on laser surgery power delivery systems for Er:Yag lasers operating at 2.94 microns. Hoya researchers use a step index (multimode) Fluorozirco-aluminate glass fiber coated with Teflon FEP and a UV curable polymer with a core/cladding diameter ratio of 450/500 (microns). Their objective was to achieve a NA of 0.22 with a transmission loss of less than 0.1 dB/m and a deliverable energy level of 800 mJ/pulse. The minimum bending radius should be less than 30 mm and the number of bending cycles should exceed 4 x 104 cycles. They have already achieved 90% transmission efficiency over 2.4 m lengths for an input power density of 80 kW/mm2. They prefer the AlF3-based fibers over the ZrF4 fibers, because of their chemical, thermal, and mechanical durability, as well as their high damage threshold at Er:Yag laser wavelengths. The effort involves four researchers.

Optical Waveguide Components

Under Y. Yokoo, Hoya researchers are involved in waveguide optical device development for both optical communication and optical signal processing applications. Their key emphasis is placed on device design, manufacturing processes, and packaging and testing. They have developed lithium-tanatalate- and lithium-niobate-based acousto-optic modulators and polarizing couplers for optical communication at 1.3 microns and 1.55 microns wavelengths, as well as multichannel modulators, phase modulators, acousto-optic modulators, frequency shifters, and polarizing couplers for signal processing at 633 and 830 nm. One low-cost system objective is the realization of a fiber-optic gyro.

Microlens Development

Led by K. Matsumoto, another technology platform under development at Hoya is the fabrication of quartz microlens arrays. This is a 4- to 5-year program, 50% supported by the division R&D and 50% by the R&D center. These lenses can be made 3 to 200 microns in diameter with 0.5 to 20 microns in height in spherical convex form but with spatial arbitrary arrangement. They are transparent in the UV region and possess high mechanical strength and chemical durability. The NA ranges from 0.1 to 0.4, and the array uniformity is 5% over 3 inches. Although not demonstrated, the company believes it can apply this technology to anamorphic systems; however, Hoya researchers are presently looking for applications for this technology. They consider NSG to be their main competitor in this area.

Nonlinear Optics Program

The objective for this 10-year government-supported program is to develop all optical means for ultrafast switching devices using 3rd order nonlinearities. This project, led at Hoya by S. Omi, includes eight other corporations and four universities. It investigates alternative ways to achieve ultrafast switching devices, including doped glass, organic materials, and thin films. Participating firms do share the information formally through 3 to 4 review meetings per year. HoyaÍs goal is to achieve devices with time responses in the order of 100 fs and a figure of merit of abs(chi^3)/alpha = 10^(-9) Hoya has developed a glass doped with nm-scale copper microparticles that provides abs(chi^3)/alpha = 10^(-11) - 10^(-11) for microP of about 100A radius and time delays of about 0.7 ps. As major competitors, Hoya cites Sumitomo and BASF AEG. Hoya expects the market for ultrafast devices to materialize in the early 21st century.

KTP Crystal Growth

Another area of present research at Hoya R&D center, under K. Sato, is the development of new growth techniques for large-size high-quality KTP crystals for Q switching applications. One of the center's customers is Lawrence Livermore Labs. Existing growth methods such as flux method and slow cooling lead to growth with sector boundaries limiting the physical dimensions of the crystals and their optical quality. A new growth technique that is a flux method under constant temperature allowed Hoya researchers to grow defect-free KTP crystals with 8 x 11 x 15 mm dimensions. They consider their main competition to be China and Professor Sasaki's group in Japan. They are looking presently for more applications for their crystals.

Silicon Carbide Thin Films

The electronics section in the R&D center is involved in the heteroepitaxial growth of 3C-SiC on Si substrates by gas-source, low-pressure CVD. Historically, Hoya started to grow polycrystalline SiC for use as X-ray mask material. Having this technology available, H. Mitsui leads Hoya researchers in investigating the use of single crystalline SiC as a material for electronic devices. Indeed, SiC offers a wide bandgap (2.2 ev), high electron mobility (1000 cm2/V/sec), high breakdown voltages, and semiconductor behavior at high temperatures. In addition, it has good chemical stability, radiation durability, and mechanical strength. So far, researchers at the R&D center have grown single crystalline 0.05 to 1.2 microns thick, n-type 3C-SiC on (001) silicon substrate with excellent uniformity. However, the electron mobility is limited to less than 100 cm2/V/sec, possibly due to misfit dislocations on films with carrier densities of 5x1016 to 5x1018 cm-3. Hoya researchers indicated that they are also contemplating using 3C-SiC thin films as a buffer material on silicon to enable the growth of other materials, including diamond, GaN, PZT, and BaTiO3.


Dr. U. Tomita showed the JTEC team the analytical instruments facility for surface, composition and other analyses. The team saw two sets of SEMs and two different kinds of X-ray Photoelectron Spectroscopy (ESCA) machines, one U.S.-made (Perkin-Elmer), and one Japanese-made. The team also was shown facilities for inductively-coupled plasma atomic emission spectroscopy (ICP), atomic absorption spectroscopy, X-ray fluorescence analysis, and ion chromatography (IC). The facility included, in addition, a transmission electron microscope (TEM), a scanning ultrasonic acoustic microscope (SAM), Fourier transform infrared spectroscopy (FT-IR), a microscratch tester, and a thermal mechanical analyzer. The center had also access to a nuclear magnetic resonance (NMR) machine and an X-ray diffractometer.


During discussions, Dr. Shiro Takahashi pointed out the severe competition in the area of crystal glassware from Eastern Europe. He pointed out that the lead content in the glassware is becoming an important issue; however, Japanese officials have not yet decided when lead free-glass should be mandated. He asked about the situation in the United States. Another point discussed was the tight government control over vision care products such as intraocular lenses (IOLs). When asked how research ideas are generated and how decisions are made to phase out or start a research program, Hoya representatives said that roughly 50% of ideas are generated by researchers at the center and another 50% by the divisions. Dr. Takahashi is responsible for the ultimate decision-making on the projects. Monthly progress review meetings are held with division representatives.

Most researchers have a master's degree in the area of optics. Few have PhDs; however, some researchers visit Japanese universities or government labs.

Published: February 1996; WTEC Hyper-Librarian