TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: In the device: a layer containing a conducting polymer is disposed at least between one electrode and the light emitting layer so that the layer containing a conducting polymer is adjacent to the electrode; an insulation layer having a thickness of 2 nm or less is disposed at least between one electrode and the light emitting layer so that the insulation layer is adjacent to the electrode; a layer comprising an electron transporting compound is disposed between the cathode and the light emitting layer so that the layer comprising an electron transporting compound is adjacent to the light emitting layer; a layer comprising a hole transporting compound is disposed between the anode and the light emitting layer so that the layer comprising a hole transporting compound is adjacent to the light emitting layer; and a layer comprising an electron transporting compound is disposed between the cathode and the light emitting layer so that the layer comprising an electron transporting compound is adjacent to the light emitting layer, and a layer comprising a hole transporting compound is disposed between the anode and the light emitting layer so that the layer comprising a hole transporting compound is adjacent to the light emitting layer.    TECHNOLOGY FOCUS - POLYMERS - Preparation: No preparation method is given. EXAMPLE - A solution of hydrogen bromide and acetic acid (200 pbw) was added to 4-(4-propylcyclohexyl)ethylbenzene (23 parts by weight (pbw)) and p-formaldehyde (12 pbw), under inert atmosphere, and the mixture was stirred at room temperature for 1 hour, then, heated at 85 degrees C for 40 hours. After cooling to room temperature, ion-exchanged water was added, and the product separated was recovered. The recovered product was washed with water several times, then, dried under reduced pressure to obtain monomer-1 (22 pbw). The monomer-1 (4.2 pbw) and 2-methoxy-5-(2-ethylhexyloxy)-p-xylylene dichloride (0.067 pbw) were dissolved in dry 1,4-dioxane (350 pbw), under inert atmosphere, nitrogen was bubbled through the solution for 15 minutes for deaeration, then, the solution was heated to 95 degrees C. To this solution, a solution of potassium tert-butoxide (2.9 pbw) and dry 1,4-dioxane (40 pbw) was added over 5 minutes dropwise. Further, the solution was heated to 97 degrees C, then, a solution of potassium tert-butoxide (2.24 pbw) and dry 1, 4-dioxane (30 pbw) was added dropwise over 1 minute, and the solution was kept at 98 degrees C for 2 hours. Then, the solution was cooled to 50 degrees C, and to this was added a mixed solution of acetic acid/1,4-dioxane for neutralization. After cooling to room temperature, the resulted solution was poured into ion-exchanged water under stir. Then, the precipitate was filtrated, and washed with methanol. This was dried under reduced pressure at 50 degrees C, then, purified to obtain polymer as polymeric fluorescent substance (0.3 pbw).