DIFFUSER

Abstract

A diffuser includes a glass material and a plurality of scattering particles. The scattering particles are spread in the glass material, where the scattering particles are inorganic materials. The haze of the diffuser is larger than 99%, whereas the thickness of the diffuser ranges between 100 m and 350 m.

Claims

1. A diffuser comprising: a glass material: a plurality of scattering particles spread in the glass material, wherein the scattering particles are inorganic materials, wherein a haze of the diffuser is larger than 99%, whereas a thickness of the diffuser ranges between 100 m and 350 m.

2. The diffuser of claim 1, wherein the haze of the diffuser is still larger than 99% when a temperature of the diffuser ranges between 200 C. and 500 C.

3. The diffuser of claim 1, wherein a total transmittance (T.T) of the diffuser ranges between 35% and 56%.

4. The diffuser of claim 1, wherein a parallel transmittance (P.T) is less than 0.3%.

5. The diffuser of claim 1, wherein a transmittance of the diffuser over a wavelength range of 400 nm to 700 nm ranges between 20% and 40%.

6. The diffuser of claim 1, wherein a refractive index of the glass material is less than a refractive index of each of the scattering particles.

7. The diffuser of claim 6, wherein the refractive index of the glass material ranges between 1.4 and 1.6, whereas the refractive index of each of the scattering particles ranges between 1.7 and 2.61.

8. The diffuser of claim 1, wherein a plurality of ingredients of the scattering particles comprises at least one of Al.sub.2O.sub.3, ZnO, CaO, MgO, BaO, SrO, ZrO.sub.2, Ta.sub.2O.sub.5, Y.sub.2O.sub.3, La.sub.2O.sub.3, GeO.sub.2, Nb.sub.2O.sub.5, and TiO.sub.2.

9. The diffuser of claim 1, wherein a particle size of each of the scattering particles ranges between 5 m and 60 m.

10. The diffuser of claim 1, wherein a weight percentage of the scattering particles ranges between 3% and 10%.

11. The diffuser of claim 1, wherein a variation in transmittance of the diffuser is less than 1% when a ray of light over a wavelength range of 400 nm to 700 nm is incident to the diffuser at an incident angle of 0 to 45 degrees.

12. The diffuser of claim 1, wherein a variation in reflectance of the diffuser is less than 1% when a ray of light over a wavelength range of 400 nm to 700 nm is incident to the diffuser at an incident angle of 0 to 45 degrees.

13. The diffuser of claim 1, wherein a glass-transition temperature (Tg) of the glass material ranges between 500 C. and 670 C.

14. The diffuser of claim 1, wherein a Young's modulus of the diffuser ranges between 50 Gpa and 75 Gpa.

15. The diffuser of claim 1, wherein a hardness of the diffuser ranges between 450 Kgf/mm.sup.2 and 550 Kgf/mm.sup.2.

16. The diffuser of claim 1, wherein a surface roughness of the diffuser ranges between 550 nm and 700 nm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:

[0010] FIG. 1 is a cross-sectional view of a diffuser in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0011] The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of embodiments of this invention are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed.

[0012] FIG. 1 is a cross-sectional view of a diffuser in accordance with an embodiment of the present invention. Referring to FIG. 1, the diffuser 100 includes a glass material 110 and a plurality of scattering particles 120, where the scattering particles 120 are all inorganic materials and spread in the glass material 110. Thus, all of the ingredients of the diffuser 100 can be inorganic materials. Compared with organic materials, the diffuser 100 is resistant to ultraviolet (UV) light and not easy to deteriorate after long irradiation with UV light. The haze of the diffuser 100 is larger than 99%. The thickness T1 of the diffuser 100 ranges between 100 m and 350 m, for example, between 150 m and 300 m.

[0013] Since the thickness T1 of the diffuser 100 is less than 500 m (e.g. between 100 m and 350 m), the diffuser 100 has the sufficiently thin thickness T1 to help the diffuser 100 install in the existing mobile device, so that the diffuser 100 is suitable for use in the photo sensor of the mobile device. The diffuser 100 can be used as a cosine corrector. In addition to mobile devices, the diffuser 100 also can be applied to some optical devices, such as a photometer. For example, the diffuser 100 can be installed in an optical fiber connector, such as SMA (Sub Miniature A) or FC (Ferrule Connector), so that the rays of light received by the diffuser 100 can be transmitted to a photo sensing chip, such as charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS), through an optical fiber.

[0014] In addition, it is worth noting that the diffuser 100 can be connected to a light emitting device and used for scattering the rays of light to diverge or uniform the light from the light emitting device, in which the light emitting device is such as a light emitting diode (LED). Thus, the diffuser 100 also can be applied to the light emitting device, such as a light fixture, so that the diffuser 100 is not limited to the use of the photo sensor.

[0015] The glass-transition temperature (Tg) of the glass material 110 may range between 500 C. and 670 C. The diffuser 100 can be resistant to a temperature between 200 C. and 500 C. That is, when the temperature of the diffuser 100 ranges between 200 C. and 500 C., the haze of the diffuser 100 is still larger than 99%. Accordingly, even if the diffuser 100 is in a high temperature environment, for example, the inside of a reflow oven during the reflow soldering, the diffuser 100 can keep a certain or constant haze to maintain the desired optical effect, thereby reducing or avoiding deviations in the sensing result of the photo sensor.

[0016] A particle size of each scattering particle 120 ranges between 5 m and 60 m, and a weight percentage of these scattering particles 120 may range between 3% and 10%. The refractive index of the glass material 110 is less than the refractive index of each of the scattering particles 120. For example, the refractive index of the glass material 110 may range between 1.4 and 1.6, whereas the refractive index of each of the scattering particles 120 may range between 1.7 and 2.61. The glass material 110 may include at least one kind of ingredient selected from SiO.sub.2, B.sub.2O.sub.3, Al.sub.2O.sub.3, ZnO, CaO, BaO, SrO, MgO, Na.sub.2O, K.sub.2O, and ZrO. That is, the glass material 110 may include any combination of the above ingredients.

[0017] SiO.sub.2 and B.sub.2O.sub.3 can form a network structure of glass. SiO.sub.2 can improve thermal stability, chemical stability, and mechanical strength, whereas B.sub.2O.sub.3 can be used as flux to reduce a melting temperature and reduce viscosity to help ingredients homogeneous. ZnO, CaO, BaO, SrO, MgO, Na.sub.2O, and K.sub.2O are all modifiers outside the network structure, in which ZnO and MgO can improve stability and weatherability, and ZnO can reduce coefficient of thermal expansion (CTE). CaO, BaO, and SrO can reduce the viscosity and help ingredients melted and homogeneous. Na.sub.2O and K.sub.2O can be used as flux to reduce the melting temperature. Al.sub.2O.sub.3 can improve both the thermal stability and the mechanical strength and increase the refractive index, whereas ZrO can improve the chemical stability.

[0018] The ingredients of the scattering particles 120 with the refractive index ranging between 1.7 and 2.61 include at least one of Al.sub.2O.sub.3, ZnO, CaO, MgO, BaO, SrO, ZrO.sub.2, Ta.sub.2O.sub.5, Y.sub.2O.sub.3, La.sub.2O.sub.3, GeO.sub.2, Nb.sub.2O.sub.5, and TiO.sub.2. For example, all of the scattering particles 120 can be made of the same material. Alternatively, some scattering particles 120 can be made of one kind of material (e.g. ZnO), and other scattering particles 120 can be made of another at least one kind of material (e.g. MgO).

[0019] A following Table (1) lists eight samples 1 to 8 based on the diffuser 100 made by employing different ingredients and ratios.

TABLE-US-00001 TABLE 1 Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 Sample 8 SiO.sub.2 weight 16.07 13.48 21.19 11.54 15.92 14.98 13.91 36.45 percentage (%) B.sub.2O.sub.3 weight 43.5 36.49 57.35 31.23 43.09 24.66 31.49 39.9 percentage (%) Al.sub.2O.sub.3 weight 7.91 6.22 18.06 percentage (%) ZnO weight 8.25 23.13 11.3 9.46 percentage (%) MgO weight 21.46 percentage (%) SrO weight 50.03 percentage (%) CaO weight 40.43 24.83 percentage (%) BaO weight 57.23 percentage (%) Na.sub.2O weight 6.16 percentage (%) K.sub.2O weight 31.01 22.39 8.03 percentage (%) ZrO.sub.2 weight 2.85 percentage (%) RO weight 40.43 50.03 21.46 57.23 24.83 percentage (%) R.sub.2O weight 31.01 22.39 14.19 percentage (%) Kind and ZnO ZnO MgO Al.sub.2O.sub.3 Al.sub.2O.sub.3 CaO BaO ZrO.sub.2 weight ratio (%) 3% 6.0 10% 5% 10% 4.5% 8% 9% of scattering particles Sintering time 800 C. 700 C. 750 C. 800 C. 800 C. 650 C. 700 C. 850 C. and temperature 0.5 hour 2 hours 1.5 hours 2 hours 0.5 hour 1 hour 1 hour 1 hour Glass-transition 611 632 672 596 621 501 524 510 temperature (Tg, C.) Soften 642 673 727 635 661 542 588 554 temperature (Ts, C.) CTE 8.24 8.48 5.17 9 6.48 11.02 8.22 7.47 Refractive 1.533 1.563 1.527 1.571 1.515 1.472 1.509 1.458 index of glass Young's 58 72 61 62 66 55 50 75 modulus (Gpa) Hardness (Hk) 502 521 490 482 495 455 490 545 (Kgf/mm.sup.2) Thickness 100 200 300 200 200 250 150 350 T1 (m) Density (g/cm.sup.2) 2.41 2.32 2.56 2.3 2.49 2.62 2.47 2.58 Haze (%) 99.54 99.56 99.53 99.52 99.55 99.55 99.54 99.53 Parallel 0.25 0.24 0.2 0.26 0.22 0.23 0.24 0.18 transmittance (P.T, %) Total 55.46 55.46 42.79 55.44 49.35 51.03 52.35 38.25 transmittance (T.T, %) Diffusion 55.21 55.22 49.59 54.18 49.13 50.8 52.11 38.07 transmittance (Dif, %) Average 39.26 35.6 28.98 32.78 31.74 32.65 34.47 20.34 transmittance over wavelength range of 400 nm to 700 nm (%) Variation in 0.345 0.19 0.156 0.21 0.174 0.202 0.238 0.165 transmittance at incident angle of 0 to 45 over wavelength range of 400 nm to 700 nm (%) Variation in 0.199 0.206 0.268 0.194 0.213 0.228 0.182 0.281 reflectance at incident angle of 0 to 45 over wavelength range of 400 nm to 700 nm (%) X value in 0.1542 0.1552 0.1551 0.1548 0.155 0.1553 0.1545 0.1551 CIE 1931 chromaticity diagram Surface 553 620 580 700 611 591 688 650 roughness (nm)

[0020] In the above Table (1), the RO weight percentage means the total weight percentage of MgO, CaO, SrO, and BaO, whereas the R.sub.2O weight percentage means the total weight percentage of Na.sub.2O and K.sub.2O. The refractive index of glass in Table (1) means the refractive index, which the glass shows and is measured by a prism coupler. The diffuser 100 has a surface 101. The surface roughness in Table (1) means a surface roughness of the surface 101, for example. In addition, all of the samples 1 to 8 based on the diffuser 100 pass 85 C./85% RH 1000 HR reliability test (e.g. Temperature Humidity Test, THT). The 85 C./85% RH 1000 HR means that the samples 1 to 8 are placed in a harsh environment at a temperature of 85 C. and a relative humidity (RH) of 85% for 1000 hours. After the samples 1 to 8 are placed in the harsh environment for 1000 hours, no irrecoverable exterior defect appears in any of samples 1 to 8, and the basic optical effects of the samples 1 to 8 are unaffected.

[0021] Referring to the above Table (1), the diffuser 100 corresponds to an X coordinate of between 0.1543 and 0.1553 in CIE 1931 chromaticity diagram, whereas the roughness of the surface 101 of the diffuser 100 may range between 550 nm and 700 nm. With regard to mechanical strength, each of the samples 1 to 8 based on the diffuser 100 has Young's modulus ranging between 50 Gpa and 75 Gpa, and the hardness (HK) ranging between 450 Kgf/mm.sup.2 and 550 Kgf/mm.sup.2. Moreover, regarding the glass materials 110 of the samples 1 to 8, the weight percentage range of each ingredient is listed as the following Table (2).

TABLE-US-00002 TABLE 2 Range of weight percentage SiO.sub.2 11%~37% B.sub.2O.sub.3 24%~58% Al.sub.2O.sub.3 0%~19% ZnO 0%~24% MgO 0%~22% SrO 0%~51% CaO 0%~41% BaO 0%~60% Na.sub.2O 0%~7% K.sub.2O 0%~32% ZrO.sub.2 0%~3% RO .sup.0~58% (i.e. total weight percentage of MgO, CaO, SrO, and BaO) R.sub.2O .sup.0~32% (i.e. total weight percentage of Na.sub.2O and K.sub.2O)

[0022] With regard to optical transmittance, the total transmittance (T.T) of each of the samples 1 to 8 based on the diffuser 100 ranges between 35% and 56%. The parallel transmittance (P.T) is less than 0.3%, whereas the diffusion transmittance (Dif) ranges between 35% and 55%, where the T.T of each of the samples 1 to 8 is equal to P.T plus Dif both thereof, as shown in Table (1). The transmittances of the samples 1 to 8 over the wavelength range of 400 nm to 700 nm range between 20% and 40%. In the samples 1 to 8, the sample 1 has the largest transmittance: 39.26%, and the sample 8 has the smallest transmittance: 20.34%.

[0023] It is worth noting that the transmittance of the diffuser 100 over the wavelength range of 400 nm to 700 nm ranges between 20% and 40%, but the haze of the diffuser 100 ranges between 99.5% and 99.6%. That is, there are the largest transmittance difference of 20% and a haze transmittance of 0.1% in the samples 1 to 8. For example, the samples 1 and 8 each have a haze about 99.5%, but the samples 1 and 8 have the transmittances of 39.26% and 20.34% respectively. Therefore, under a condition of requiring the haze of 99% or more, the diffuser 100 can be designed to have varied transmittances for diverse product demands.

[0024] In addition, each of the variations in both transmittance and reflectance of the diffuser 100 is less than 1% when rays of light over a wavelength range of 400 nm to 700 nm are incident to the diffuser 100 at an incident angle of 0 to 45 degrees. Accordingly, when the diffuser 100 in a light source environment receives a plurality of external rays L1 of light, the total intensity of light L2 emitted from the diffuser 100 with the variation in the incident angle of the external ray L1 does not change largely, so that the photo sensor does not get large variation in the sensing result due to a slight change of the position or the orientation of the diffuser 100, thereby reducing or avoiding deviations in the sensing result of the photo sensor.

[0025] The diffuser 100 is mainly made by second sintering. Specifically, in manufacture of the diffuser 100, first, an initial glass is made. The initial glass can be made by sintering, in which the sintering temperature may range between 1200 C. and 1400 C., and the ingredients of the initial glass may be the same as the ingredients included by the glass material 110, such as SiO.sub.2, B.sub.2O.sub.3, Al.sub.2O.sub.3, ZnO, CaO, BaO, SrO, MgO, Na.sub.2O, K.sub.2O and ZrO.sub.2, or any combination of the preceding ingredients.

[0026] Next, the initial glass is crushed, and then ground into a glass powder, in which the particle size of the glass powder is about 80 m or less. Then, the glass powder and a plurality of scattering particles 120 are mixed together and compressed to form a compressed tablet. The weight percentage of the scattering particles 120 ranges between 3% and 10%, and the compressing process can be performed by using a hydraulic press. Next, the compressed tablet is heated, where the temperature of heating the compressed tablet can range between 650 C. and 850 C., and the time of heating may be two hours. Afterward, the compressed tablet cools off naturally. Then, the compressed tablet is cut and polished in sequence to form a sheet having a thickness ranging about between 100 m and 350 m. So far, the diffuser 100 is basically completed.

[0027] Compared with the sintering temperature of the initial glass, the temperature of heating the compressed tablet is obviously lower, and the scattering particles 120 can not melt in the temperature range of heating the compressed tablet. In other words, after heating the compressed tablet, each of the scattering particles 120 basically remains in its original shape. That is, there is a boundary existing between the scattering particle 120 and the glass material 110. Therefore, at least one peak signal corresponding to the composition of the scattering particle 120 can be detected by performing X-Ray diffraction on the compressed tablet after heated or the complete diffuser 100.

[0028] While the invention has been described in terms of what is presently considered to be the most practical and embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.