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Incandescent Light Bulb: Product Design and Innovation Soemantri Widagdo* 3M Display and Graphics Business Laboratory, St. Paul, Minnesota 55144
In this brief article, a strategy is introduced for meshing the technical advances with the fulfillment of customer needs during the development and design of new products. The concept of an innovation map is developed to connect material, process, and product technologies to the value proposition of the new products. By retracing the advances in developing incandescent light bulbs, the interplay between technical discovery and its commercialization into new products is shown. Although the design of the incandescent light bulb is presented in hindsight, this interplay is the key to the design of new products; however, unfortunately, in new product design, there are many alternatives to explore that may not be fruitful. Introduction Chemical engineers working in industry are increasingly challenged by the need to develop new products rather than new processes. This trend has accompanied the gradual shift from the manufacture of basic chemicals to industrial chemicals and consumer products. However, chemical education has been slowly changing to adapt and prepare its graduates for these challenges. Recently, a few articles have addressed this issue.1,2 Herein, as an industrial practitioner, the author intends to show that several aspects of product designssuch as materials, process/manufacturing, and product technologiessshould be simultaneously considered in the development and design of a new product. The main purpose of the materials, process/ manufacturing, and product technologies is to create a product that satisfies the customer needs, in addition to offering a competitive advantage. To achieve this, the concept of an innoVation map is developed to represent the connections between the three technological components and customer satisfaction, that is, the customer value proposition. The success of a new product often relies on the careful attention given to this interplay. Before the concept of an innovation map is introduced, consider the history of the development of the modern incandescent light bulb, which will be used to illustrate the innovation map. History of the Development of the Incandescent Light Bulb The passage of an electrical current through a filament creates light in an incandescent light bulb; the heat that is generated radiates light in the visible range. Depending on the material construction of the filaments, low- and high-wattage light bulbs are manufactured. In early 1800s, Humphrey Davy, an electrochemist, first demonstrated this concept by passing electrical current through a platinum strip. Then, in about 1820, a French inventor, de La Rue, made the first incandescent bulb by passing electrical current through a platinum coil in a vacuum glass tube. Twenty years later, Grove used a concept that was similar to that of de La Rue to light a public theater. In 1878, Joseph Swan replaced the very expensive platinum coil with a muchless-expensive carbon filament. This was the turning point of the mass production of electricity, as we know it today. * To whom correspondence should be addressed. Tel.: 651 7360515. Fax: 651 736-0710. E-mail address:
[email protected].
It was not until 1880 that Edison built the first successful commercial production of incandescent bulbs. Edison was the first to develop an electrical power supply and electricity delivery system and a manufacturing process to produce lessexpensive and longer-lasting bulbs. Because Swan first patented the method of manufacturing carbon filaments, Edison made him a business partner to gain the right to manufacture carbon filaments and commercialize an electrical power supply system to end-users. Edison’s contribution to electric lighting was not the invention of the light bulb, but rather the development of its mass production and the electrical delivery system. The major disadvantage of the carbon-based filament is the production of combustion products that turn the bulb dark black. This was overcome in 1903, when William Coolidge invented an improved method of making tungsten filaments. The tungsten filament outlasted all other types of filaments and Coolidge manufactured bulbs at practical costs. He succeeded in preparing a ductile tungsten wire by doping tungsten oxide before reduction. The resulting metal powder was pressed, sintered, and forged into thin rods. Very thin wires were then drawn from these rods. In 1906, the General Electric Company patented a method of making tungsten filaments for use in incandescent light bulbs. Tungsten filaments offer a high melting temperature and low vapor pressures, which translate to a lower evaporation rate of tungsten vapor and reduced blackening. Another GE researcher, Irving Langmuir, took advantage the ductile tungsten rods that were produced by the Coolidge process. Prior to the work of Langmuir, GE's bulbs were evacuated so that oxygen would not burn out the filaments. In the vacuum environment, low-wattage bulbs performed sufficiently well, but the tungsten wires in high-wattage bulbs performed poorly. Tungsten vapor was gradually deposited on the inside walls of the bulbs and turned them black. Langmuir realized he could suppress the tungsten evaporation by filling the light bulb with an inert gas that would not burn the filament. However, the inert gas circulated in the bulb, carrying away too much heat, which, in turn, significantly reduced the brightness of the bulb. Earlier research by Langmuir taught him that a filament wound in a tight coil would produce significantly less heat. So he invented tightly coiled tungsten filaments using the Coolidge process for producing highly ductile tungsten rods. The tightly coiled tungsten filament in an inert gas environment is the basis for his 1916 patent on the incandescent electric bulb, which continues as the basis for modern incandescent light
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Figure 1. Conventional light bulb innovation map.
bulbs. For a more-complete description of the invention of the first long-life, high-wattage, incandescent light bulb, see Langmuir.3 Innovation and Product Design of the Incandescent Light Bulb The preceding section has provided an historical account of the invention of the incandescent light bulb. Hindsight has helped us to construct the relationships among many inventions that lead to the successful production of long-life, high-wattage light bulbs. Note, however, that during the development stage of a new product, often the components of the discoveries are incomplete, and, consequently, these relationships are not clear, complicating the path to the successful commercialization of the new product. Clarity on turning technical advantage into competitive advantage is the key to commercializing a new product. In this section, an innovation map is proposed as a tool to provide a systematic way to guide new product development efforts. First, the relationship of a scientific discovery and how it is transformed into an innovation is described, followed by a discussion of the interplay between the technical developments and customer satisfaction, that is, the customer value proposition. Invention and Innovation. These terms are often used interchangeably in a casual discussion and presentation. InVention refers to a scientific discovery with a clear technical advantage over the current state-of-the-art. InnoVation, on the other hand, is the creation of business value through differentiation. The transformation of technical differentiation into customer values, satisfying the customer value proposition, is often the key for successful new product development. Innovation Map A product development effort can be technology-driven or market-driven. Market-driven, new product development starts with a known market or customer need for a solution. On the other hand, technology-driven, new product development begins with a technological invention, which involves either materials or process/manufacturing technologies. In either case, it is necessary to match the market/customer needs with the tech-
nological invention. The successful match creates product innovation, with the innoVation map providing a systematic linkage between the technology and market voices. The linkages therein, while straightforward to create, are often overlooked outside of the business world, because the technology and market voices are often owned by different organizations. For example, in many companies, the technology voice is owned by the research and development (R&D) organization, whereas the market voice is owned by the sales/marketing organization, with communication gaps created inadvertently between these organizations. Creation of the innovation map helps to bridge these gaps. Clearly, the R&D organization concentrates on technical differentiations, such as higher manufacturing speeds, lower evaporation rates, higher melting points, etc. However, although the technical staff focuses on these attributes, often they do not translate them sufficiently into customer values; that is, they do not focus on the customer value proposition. From the other perspective, with the sales/marketing organization focusing on the customer value proposition, the advantages of the technical differentiation may be undervalued. In my experience, attempts to create these linkages in the early stages of new product development have been crucial to the success of new product commercialization. The innovation map relates the technological components of product developments to the technical advantages, that is, showing the technical differentiation, and, ultimately, the satisfaction of the customer value proposition. The technological components can be classified into three categories: materials, process/manufacturing, and products technologies, as illustrated next for the design of the light bulb. The innovation map evolves during product design, being updated periodically during the new product development and commercialization processes. Returning to the product development of incandescent light bulb, consider the generation of the innovation map in Figure 1. Note that, although this map is readily generated for the light bulb in hindsight, the generation of such a map should be the objective of product design strategies. The challenge in the early 1900s was to produce long-life light bulbs, with vacuum light bulbs that had carbon filaments being the state-of-the-art, which was a technology that served consumer needs well at low-wattage requirements. At the time
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Figure 2. Halogen bulb innovation map.
of Langmuir’s invention, tungsten was considered to be the front-runner to replace carbon and platinum filaments. To construct the innovation map of the modern incandescent light bulb, one must first identify the elements of the innovation map. These elements are as follows: Materials Technology: includes platinum, carbon, tungsten, inert gases Manufacturing/Process Technology: includes the invention of the Coolidge manufacturing process of ductile tungsten rods, inert-gas-filled bulbs, vacuum bulbs, tightly coiled filaments Product Technology: includes vacuum bulbs, gas-filled bulbs, and low- and high-wattage bulbs Technical Value Proposition: low-cost manufacturing, higher melting point, lower evaporation rate. Products: includes long-life incandescent light bulbs Customer Value Proposition: involves long-life light bulbs and takes into consideration low cost, versatility of shape, light quality (warm, cool, daylight) After these various elements have been identified and placed on the appropriate layers in the map, the connectivity among them can be drawn to show the interplay between the technological elements, the technical value proposition, and ultimately the customer value proposition, as shown in Figure 1. Where there is a customer need that has not been met, such as the versatility of shape, this can be an objective for the next generation of products. To further illustrate the concept of innovation maps, consider the development of the halogen light bulb. The halogen lamp is an incandescent light bulb with a tungsten filament sealed in a small, halogen-gas-filled bulb. The lifetime of an incandescent bulb is dependent on the durability of the tungsten filament at high temperature. Variations in the thickness of the tungsten filaments leads to runaway heating, which ultimately causes the filament to fail. Thinner segments that have greater resistance experience higher temperatures, relative to thicker segments. Higher temperature leads to a higher tungsten evaporation rate, and, thus, the segment gets thinner and hotter and eventually breaks. It has been observed that halogen gases form an equilibrium reaction with tungsten at high temperature. Furthermore, the evaporated tungsten has the tendency to redeposit onto the filaments at higher temperature (thinner segments), which breaks the runaway cycle and increases the lifetime. Typically, a
halogen light bulb has a lifetime that is twice that of the conventional incandescent light bulb. In addition, halogen light bulbs have higher efficiency and a whiter color temperature. To maintain a high reaction temperature, the design of the halogen light bulb requires a tight (smaller) casing/bulb that is made of high-temperature glass or quartz. A secondary closure is added to isolate the hot halogen bulb from accidental contact. The innovation map of the halogen light bulb is shown in Figure 2. In this example, the key inventions stem from the materials (halogen gases), process/manufacturing (quartz primary casing), and product technology (secondary casing). In contrast, the innovation map for the conventional light bulb (see Figure 1) shows that the material technology is the driver of the innovation. Conclusion Innovation occurs when the voice of the marketsthat is, customerssmatches the voice of technology (materials, process/ manufacturing, and products). The innovation map is robust, and it provides the necessary linkages between the technical differentiation and the customer value proposition throughout the new product development process. Note that, although this map is readily generated for the light bulb in hindsight, the generation of such a map should be the main objective of product design strategies. Through a focus on the innovation map, the probability of successful new product introduction is increased. Acknowledgment Fruitful discussion with Prof. Warren D. Seider of the University of Pennsylvania is greatly appreciated. Literature Cited (1) Seider, W. D.; Seader, J. D.; Lewin, D. R.; Widagdo, S. Chemical Product and Process Design. In Proceedings of AspenWorld 2004, Orlando, FL, 2004. (2) Seider, W. D.; Seader, J. D.; Lewin, D. R. Chemical Product and Process Design Education. In Proceedings of FOCAPD-2004 Conference, Princeton University, Princeton, NJ, 2004. (3) Langmuir, I. Gaseous Electric Light, U.S. Patent No. 1,180,159, April 18, 1916.
ReceiVed for reView March 28, 2006 ReVised manuscript receiVed September 29, 2006 Accepted September 29, 2006 IE060391B
