1、SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefro
2、m, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions.QUESTIONS REGARDING THIS DOCUMENT: (724) 772-8512 FAX: (724) 776-0243TO PLACE A DOCUMENT
3、 ORDER; (724) 776-4970 FAX: (724) 776-0790SAE WEB ADDRESS http:/www.sae.orgCopyright 1991 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.SURFACEVEHICLE400 Commonwealth Drive, Warrendale, PA 15096-0001INFORMATIONREPORTJ2217ISSUEDOCT91Issued 1991-10PHOTOMETRIC GUIDELINES FO
4、R INSTRUMENT PANEL DISPLAYSTHAT ACCOMMODATE OLDER DRIVERS1. ScopePhysical parameters that influence the legibility of an instrument panel display include letter/graphicsize, the luminance and color difference between graphics and background, the observers luminanceadaptation level, and the level of
5、glare present. Several aspects of visual functioning deteriorate as part of thenormal aging process. These include a reduction in luminance and color contrast sensitivity, an increase insensitivity to glare, a reduction in visual accommodation capacity, and a reduction in the sensitivity to light.Th
6、is SAE Information Report provides introductory information that should be considered when settingphotometric guidelines for instrument panel displays that are designed to accommodate the older driver. Moredetailed information is provided in Section 2 of this document.2. References2.1 Applicable Pub
7、licationsThe following publications form a part of this specification to the extent specifiedherein.1. Wyszecki, G., and Stiles, W.S. (1982), Color Science: Concepts and Methods, Quantitative Data andFormula (2nd edition), New York: John Wiley and Sons.2. Poynter, D. (1988), “The Effects of Aging on
8、 Perception of Visual Displays,“ SAE 881754, Warrendale,PA.3. Poynter, D. (1991), “Contrast Sensitivity and English Letter Recognition,“ Proceedings of the 1991Human Factors Society Annual Meeting, September 26, San Francisco, CA.4. Blackwell, H.R. (1959), “Specification of interior illumination lev
9、els,“ Journal of the IlluminatingEngineering Society, June, 3173535. Blackwell, O.M., and Blackwell, H.R. (1971), “Visual performance data for 156 normal observers ofvarious ages,“ Journal of the Illuminating Engineering Society, October, 313.6. Blackwell, O.M., and Blackwell, H.R. (1980), “Individu
10、al responses to lighting parameters for apopulation of 235 observers of varying ages,“ Journal of the Illuminating Engineering Society, July,205232.7. Snyder, H.L., Lynch, E.F., Abernathy, C.N., Green, J.M., Helander, M.G., Hirsh, R.S., Hunt, S.R.,Korell, D.D., Kroemer, K.H.E., Murch, G.M., Palacios
11、, N.P., Palermo, S.A., Rinalducci, E.J., Rupp, B.A.,Smith W., Wagner, G.N., Williams, R.D., Zwahlen, H.T. (1988), “American National Standard forHuman Factors Engineering of Visual Display Terminal Workstations,“ The Human Factors SocietyInc., Santa Monica, CA, ANSI/HFS 100188.8. Boynton, R.M., Rina
12、lducci, E.J., and Sternheim, C. (1969), “Visibility losses produced by transientadaptational changes in the range from 0.4 to 4000 footlamberts,“ Illuminating Engineering, 217227.SAE J2217 Issued OCT91-2-9. Osaka, N. (1985, July), “The effects of VDU color on visual fatigue in the fovea and peripher
13、y of thevisual field,“ Displays, 138140.10. Matthews, M.L. (1987), “The influence of colour on CRT reading performance and subjective comfortunder operational conditions,“ Applied Ergonomics, 18.4, 323328.11. Galer, M.D., and Simmonds, G.R.W. (1985), “The lighting of car instrument panelsdrivers res
14、ponsesto five colours,“ SAE 850328, Warrendale, PA.12. Uchikawa, K., Uchikawa, H., and Kaiser, P.K. (1984), “Luminance and saturation of equally brightcolors,“ Color Research and Application, 9(1), 514.13. Poynter, D. (1988), “Variability in brightness matching of colored lights,“ Human Factors, 30(
15、2), 143151.2.2 TerminologyThe spectral power distribution of a light source can be described as a location in any one ofseveral three-dimensional color spaces 1.1 In most of these spaces, two of the dimensions correspond to theperceived color of the light. The third dimension (luminance) corresponds
16、 to the perceived intensity of the light.The luminance dimension can be thought of as representing perceptual brightness, although other factorsaside from luminance can affect how bright a light source appears to be (e.g., the size of the source).“Luminance Contrast“ is a measure of the difference b
17、etween the luminance of a display letter/graphic and theluminance of its spatially contiguous background. There are several commonly used indices of luminancecontrast. The one used in this document is as in Equation 1:(Eq. 1)where:Lmax and Lmin are the larger and smaller of stimulus and background l
18、uminance, respectively.The term “Color Contrast“ refers to the difference in color between the letter/graphic and its background. Thereare several ways to quantify color contrast. One of the most common indices is the distance in color spacebetween the coordinates for the letter/graphic and the coor
19、dinates for the background. In this document,luminance contrast and color contrast are considered separately; therefore the term color contrast refers to atwo-dimensional distance across a plane in color space perpendicular to the luminance dimension.Finally, the term “Adaptation Luminance“ refers t
20、o the level of light that the drivers visual system is adapted to.In an automobile, for example, the adaptation luminance will most often be the average luminance of thedrivers field of view through the windshield. During daytime driving, the adaptation luminance will typically bemany times higher t
21、han the luminance of displays in the interior of the automobile.3. Photometric Guidelines for IP Displays3.1 Luminance ContrastThe minimum value of luminance contrast required to ensure display legibility is not aconstant. It depends upon the amount of color contrast present, the size of letters/gra
22、phics, display luminance,adaptation luminance, driver age, and other contextual factors. For example, the studies of references 2,3show that changing the height of display letters from 0.15 degrees to 0.3 degrees can reduce contrastrequirements by a factor of 3. Contrast requirements for relatively
23、dark ambient conditions (less than 0.1 cd/m2)can be 20 times greater than contrast requirements for moderate to bright conditions (greater than 50 cd/m2)4,5,6. Adding a color difference between letters and background also has a strong impact on minimumluminance contrast. For example, a distance betw
24、een letters and background of 0.10 in the 1976 colorplane can reduce luminance contrast requirements to 0.0. The effect of color contrast on legibility dependsupon letter size and display luminance 3,7. Color contrast improves legibility the most when letters/graphicsare relatively large and display
25、 luminance is relatively high.1. The brackets represent the references.LmaxLminLmin-vSAE J2217 Issued OCT91-3-The presence of glare sources, and a difference between display luminance and adaptation luminance, canboth increase contrast requirements dramatically 6,8. Older drivers are much more sensi
26、tive to glare than areyounger drivers.Although there is no single value of contrast that is optimal for all viewing contexts, the fact that older drivers asa group require much higher contrast than younger drivers is well documented 2,3,5,6. On average, driversover 60 years old will require at least
27、 twice as much contrast as drivers under 30 years of age. This is true fordaytime and nighttime visibility, but the differences between young and old are more dramatic at night.3.2 Color UsageWhen the background of a display letter/graphic is not black (i.e., when it has some perceivableluminance le
28、vel), colors should be chosen for graphic and background that are distant from one another incolor space. This will help to ensure adequate legibility.Spectrally pure (i.e., monochromatic) blues and reds should be avoided for light emitting displays. Differentwavelengths require different levels of
29、visual accommodation (i.e., lens refractive indices). Using pure red andblue symbols within the same display can result in frequent refocusing of the eye, leading to visual fatigue andblurry images. Such color combinations can also produce a distance illusion in which one color appears to becloser t
30、han the other. These effects are more pronounced when letters/graphics are relatively high inluminance and placed against a low luminance background. Because visual accommodation is more difficultfor the aging eye, using pure blues and reds (especially together on the same display) is more of a prob
31、lem forthe mature driver.For CRT displays, red-blue phosphor combinations should also be avoided for letters and graphics. The eyesometimes focuses preferentially on one of these colors (usually red). The result, a fuzzy “halo“ effect aroundthe image (usually blue), can be visually annoying and can
32、make the image hard to resolve.3.3 Color PreferenceIn general, older drivers should find yellow and green colors easier to focus on than redsand blues, and most studies seem to indicate that older drivers prefer the mid-spectrum colors 2,9,10,11.However, it is important to remember that spectral pur
33、ity and intensity are very important factors that influencethe acceptability of a display color for older drivers. Stating that designers should avoid blue altogether wouldtherefore be inappropriate. Very pure, end-of-the-spectrum blue should be avoided for graphic colors,however. These wavelengths
34、are hard to focus on, the older eye is relatively insensitive to them, and fine detailis especially difficult to resolve when illuminated with these wavelengths.In general, the broader the spectral power distribution of the light emitted by the display, the less concerneddesigners need to be about t
35、he effects of color on display legibility.3.4 Brightness PreferenceBecause the older eye scatters light more than the younger eye, older drivers aremore sensitive to glare from instrument panel lighting during night driving. As a result, older drivers mayactually prefer lower brightness levels for d
36、isplay lighting than younger drivers, despite the fact that the oldereye is generally less sensitive to light than the younger eye 2. To avoid discomfort glare problems for the olderdriver, allow the driver control over instrument panel light levels.Also consider that the perceived brightness of dis
37、play colors is not always consistent with the luminance of thecolor. Perceived brightness varies with the size of the display graphics, the predominant hue and the saturationof the color 2,12,13.SAE J2217 Issued OCT91-4-3.5 GlossFor displays that may be exposed to bright ambient lighting (e.g., heat
38、er and air-conditioning controlbuttons, radio and wiper controls, etc.), the gloss of the display graphics and their backgrounds can havesignificant effects on display legibility. If the graphic color is lighter than the background color (e.g., a whitegraphic on a gray background) and the gloss of t
39、he background material is higher than that for the graphic,legibility of the display can be greatly reduced when viewed at specular angles. This legibility problem can beeliminated by making the graphic gloss higher than the background gloss. The background should be glossierthan the graphic if the
40、graphic color is darker than the background color.PREPARED BY THE SAE MATURE DRIVER STANDARDS COMMITTEESAE J2217 Issued OCT91RationaleNot applicable.Relationship of SAE Standard to ISO StandardNot applicable.ApplicationPhysical parameters that influence the legibility of an instrument panel display
41、include letter/graphic size, the luminance and color difference between graphics and background, the observersluminance adaptation level, and the level of glare present. Several aspects of visual functioningdeteriorate as part of the normal aging process. These include a reduction in luminance and c
42、olorcontrast sensitivity, and increase in sensitivity to glare, a reduction in visual accommodation capacity,and a reduction in the sensitivity to light. This SAE Information Report provides introductory informationthat should be considered when setting photometric guidelines for instrument panel di
43、splays that aredesigned to accommodate the older driver. More detailed information is provided in Section 2 of thisdocument.Reference Section1. Wyszecki, G., and Stiles, W.S. (1982), Color Science: Concepts and Methods, Quantitative Data andFormula (2nd edition), New York: John Wiley and Sons.2. Poy
44、nter, D. (1988), “The Effects of Aging on Perception of Visual Displays,“ SAE 881754,Warrendale, PA.3. Poynter, D. (1991), “Contrast Sensitivity and English Letter Recognition,“ Proceedings of the 1991Human Factors Society Annual Meeting, September 26, San Francisco, CA.4. Blackwell, H.R. (1959), “S
45、pecification of interior illumination levels,“ Journal of the IlluminatingEngineering Society, June, 3173535. Blackwell, O.M., and Blackwell, H.R. (1971), “Visual performance data for 156 normal observers ofvarious ages,“ Journal of the Illuminating Engineering Society, October, 313.6. Blackwell, O.
46、M., and Blackwell, H.R. (1980), “Individual responses to lighting parameters for apopulation of 235 observers of varying ages,“ Journal of the Illuminating Engineering Society, July,205232.7. Snyder, H.L., Lynch, E.F., Abernathy, C.N., Green, J.M., Helander, M.G., Hirsh, R.S., Hunt, S.R.,Korell, D.D
47、., Kroemer, K.H.E., Murch, G.M., Palacios, N.P., Palermo, S.A., Rinalducci, E.J., Rupp,B.A., Smith W., Wagner, G.N., Williams, R.D., Zwahlen, H.T. (1988), “American National Standard forHuman Factors Engineering of Visual Display Terminal Workstations,“ The Human Factors SocietyInc., Santa Monica, C
48、A, ANSI/HFS 100188.8. Boynton, R.M., Rinalducci, E.J., and Sternheim, C. (1969), “Visibility losses produced by transientadaptational changes in the range from 0.4 to 4000 footlamberts,“ Illuminating Engineering, 217227.9. Osaka, N. (1985, July), “The effects of VDU color on visual fatigue in the fo
49、vea and periphery of thevisual field,“ Displays, 138140.10. Matthews, M.L. (1987), “The influence of colour on CRT reading performance and subjective comfortunder operational conditions,“ Applied Ergonomics, 18.4, 323328.11. Galer, M.D., and Simmonds, G.R.W. (1985), “The lighting of car instrument panelsdriversresponses to five colours,“ SAE 850328, Warrendale, PA.12. Uchikawa, K., Uchikawa, H., and Kaiser, P.K. (1984), “Luminance and saturation of equally brightcolors,“ Color Research and Application, 9(1)
