Lead in Frit glass. used within Vacuum Fluorescent Displays VFD. May Futaba Corporation Electronic Components Division Engineering Group

Transcription

1 PB Lead in Frit glass used within Vacuum Fluorescent Displays VFD POSSIBLE ALTERNATIVES & PROPOSAL FOR AN ENTRY FOR FURTHER EXEMPTIONS FROM THE REQUIREMENTS OF DIRECTIVE 2000/53/EC END- OF- LIFE VEHICLES ARTICLE 4(2)(b) ANNEX II FOR SPECIFIC APPLICATIONS OF LEAD. May 2006 Futaba Corporation Electronic Components Division Engineering Group ELV exemption_request_futaba_vfd.doc 1/1

2 Content: 1.Explanation of VFD technology / where lead in VFD is used and why it is needed 2.Checklist to ask for an exemption ELV exemption_request_futaba_vfd.doc 2/2

3 1. Explanation of VFD technology / where lead in VFD is used and why it is needed Vacuum Fluorescent Display (VFD)as Electrical component VFD is an electrical component with display function. VFD consists of the following parts: a front and a base plate constitute a vacuum envelope, in which the filament cathode, grid and anode are arranged to form electrodes. The vacuum vessel structure enables VFD to emit electrons from filaments and grids that control the movement of electrons. When the electrons are applied to luminescent material (anode), VFD creates the display image intended by users. VFD needs to fulfill all of the following requirements to function as the display. The requirements and the portions of VFD Requirements; 1.To retain the vacuum which maintain the performance of filaments and allow electrons to move in space within VFD, 2.To fix external lead and grid, and electrically connect them to wire, 3.To keep electric insulation of each display segment, and 4.To use proper glass materials each of which has not only either vacuum, conductive or insulative property, but also physical properties (thermal expansion coefficient, softening temperature, etc.) in accordance with VFD production process. In order to fulfill the requirements, VFD includes lead in a glass matrix compound Requirements and portions (locations) including lead in glass Requirements portions of usage VFD structure To retain the vacuum performance filaments for of and electron movement To fix lead and grid and connect them to wire lead in glass for sealing of package (vacuum vessel) lead in glass for grid electrode bonding material lead in glass for electrode terminal lead in glass for electrode contact of wires and anode electrode 3Grid Electrode Bonding Material 2 1Sealing Material 1 2Thick-Film Insulator 1 Sealing Material 2 Fig.1 Anode Electrode 5Electrode Contact 3Grid Electrode Bonding Material 1 1Sealing Material 1 6Solder 4Internal Electrode Terminal Cross section of a VFD External Lead ELV exemption_request_futaba_vfd.doc 3/3

4 To keep electric insulation of each display segment lead in glass for film insulator 2.Checklist to ask for an exemption PROPOSALS FOR FURTHER EXEMPTIONS FROM THE REQUIREMENTS OF DIRECTIVE 2000/53/EC END- OF- LIFE VEHICLES ARTICLE 4(2)(B) ANNEX II FOR SPECIFIC APPLICATIONS OF LEAD No.1: Lead (1) Lead in lead frit glass of VFD s Criteria 1. Please describe the material / component of the electrical and electronic equipment that contains the hazardous substance. Please indicate the type and quantity of the hazardous substance used in the homogenous material. Please indicate the quantity of the substance in absolute numbers and in percentage by weight in homogenous material. Please indicate the functionality of the substance in the material of the equipment. Information Please provide supporting technical and scientific evidence Pb Weight (g) Internal Electrode Pb (%) Sealing Thick-Film Terminal, per Total Material Insulator Bonding VFD Material, Contact Outsize 12g 0.2g 0.6g 12.8g 6% Midsize 5g 0.1g 0.1g 5.2g 9% Small size 1g 0.05g 0.05g 1.1g 12% ELV exemption_request_futaba_vfd.doc 4/4

5 Please also provide an estimate of the annual quantities of the hazardous substance used in this particular application. Pb (%) per Homogene ous Material 74% 52% 44% Lead Glass with lead Functionality Dropping softening point of the glass Bonding metal material Electrically connecting internal electrode Vacuum sealing of VFD An estimate of annual quantities: 90 ton (bases on 2005 production. It will be increasing or decreasing.) 2. Please explain why the elimination or substitution of the hazardous substance via design changes or materials and components is currently technically or scientifically impracticable. No substitute glass material, which gives a low softening point enough to be sintered around 450 and maintain vacuum within VFD, is available for sealing. The candidates of lead free alternatives have to satisfy the requirements below: 1)Capable of adjusting the softening temperature between 350 ~600, 2)Having chemical stability inactive to organic material used for paste, 3) Having expansion coefficient equal to that of the glass which constitutes the package, 4) Having chemical resistance and weatherability as seal glass which consists vacuum components. ELV exemption_request_futaba_vfd.doc 5/5

6 Even though Bismuth glasses, zinc borate glasses, and tin phosphate glasses, known as the candidates of lead free alternatives, cannot be commercially applied, because they do not satisfy the all requirements for manufacturing VFD. Also, the estimated price of VFD used such candidates is almost double because of increase of material cost: The present situation is shown bellow: Required Properties Softening Temperature: Adjustable between Reactivity to organic material Lead Glasses Bismuth Glasses Lead-Free Glasses Zinc Borate Tin Phosphate Glasses Expansion Coefficient Same as glass Chemical resistance and whetherability as seal glass? : very good : good : fair : bad?:no information 3. Please indicate if the negative environmental, health and/or consumer safety impacts caused by substitution are likely to outweigh the environmental, health and/or consumer safety benefits. Therefore, lead free alternatives are currently impossible to be applied for VFD both commercially and technically. In accordance with the result of the test stated in section 6, it would appear that the reliability of the lead-free glass for car meter is inferior to currently used glass with lead because of the inferior weatherability of the lead-free glass. If it would be used for car meter, it would jeopardize human s ELV exemption_request_futaba_vfd.doc 6/6

7 If existing, please refer to relevant studies on negative impacts caused by substitution. security because of some problems such as display error. There are no negative impacts for human s health if the one directly touches VFD (the glass has similar constituent as crystal glass with lead used in EU). Nevertheless, people usually never touch VFD directly because VFD is used as a component for a product. When the product is disposed, separate disposal is possible because VFD is detachable from such products. However, some cost occurs for separate disposal. 4. Please indicate if feasible substitutes currently exist in an industrial and/or commercial scale. Please indicate the possibilities and/or the status for the development of substitutes and indicate if these substitutes will be available by 1 July 2006 or at a later stage. 5. Please indicate if any current restrictions apply to such substitutes. There are no alternatives for most of the applications, except those for lead in glass electrically connecting internal electrode. Application is still investigated considering with the drastic change of process conditions. However, lead free alternatives are currently impossible to be applied commercially by 1 July The estimation when substitutions will be available is impossible. None If yes, please quote the exact title of the appropriate legislation/regulation. 6. Please indicate the costs and benefits and advantages and disadvantages of such substitutes. If existing, please refer to relevant There is no benefits and advantages. Disadvantages are decrease of VFD s reliability because of low stability of glasses and increase of material cost, in particular when using lead-free glasses (see section 2). ELV exemption_request_futaba_vfd.doc 7/7

8 studies on costs and benefits of such substitutes. Pressure Test (VFD) Pressure distributed on package seal detachment defect (%) glass with lead lead-free glass atmosphere pressure+1.5kgf/cm2 0 0 atmosphere pressure+1.8kgf/cm2 0 0 atmosphere pressure+2.0kgf/cm atmosphere pressure+2.5kgf/cm Weather Resistance Test (stability evaluation against moisture under high temperature) when glass component responds with moisture, weight increases. hours at temperature 70degree increacing rate of weight(%) C / moisture 90% glass with lead lead-free glass observed fact: minute cracks occurred on the surface of lead-free glass In accordance with the above result, it turns out that lead-free glass is inferior to currently used glass with lead in the point of withstand pressure and weatherability. Lead-free glass needs to have at least the same behavior. 7. Please provide any other relevant information that would support your application for an additional exemption. VFD comply with RoHS directive. Lead is the only hazardous substance needed within VFD s. Here we refer to Annex Pt.5 of exemptions: lead in glass of cathode ray tubes, electronic components and fluorescent tubes. ELV exemption_request_futaba_vfd.doc 8/8